The ’70s are widely regarded as the cinema’s second gilded age, and with good reason.

As the audience shrank to date movie kids, action and genre addicts who thought drive-ins were the best way to watch a movie or discerning, sophisticated filmgoers, as the studios changed hands and new ownership abandoned old genres and formulas in search of something that might draw a crowd, a new generation of filmmakers announced itself with daring films, and later in the decade, the invention of the modern blockbuster.

But before “Jaws” and “Star Wars” changed everything, “Five Easy Pieces,” “The Godfather,” “Harold and Maude,” “Chinatown,” “The Conversation” and “One Flew Over the Cuckoo’s Nest” were mulled over and debated by the major magazine critics of the era, and their readers. “All the President’s Men” was history illuminated and summed up just as it happened. And “Shampoo” and “Network” reminded us that comedy could be social commentary and satire.

And then “Heaven’s Gate” all but killed off risky and smart cinema. “Raiders of the Lost Ark” chiseled the popcorn blockbuster business model in stone, and it was all over.

But “Being There” ended a great cinema decade with a glorious, witty and wry flourish. It’s no surprise that it took years of effort and many potential stars turning it down before Jerzy Kosinski’s mirror-on-America novel could finally reach the screen. After Watergate, we were ready. As we prepared to put a dotty, myopic commie-hating movie star in the White House, we needed a movie that could explain how that might happen.

Peter Sellers, director Hal Ashby and Kosinski created a mythic satire of the attention span of a culture than embraces the new and the unknown as “fresh,” even when it isn’t fresh or profound or even smart, a timeless film that pokes at race, skewers clueless media, conservatism and the oligarchs who control it to rule over The Masses, a masterpiece that would come out just in time for The Reagan Era.

It’s all in the perception — the posturing and media gullibility in celebrating the surface gloss and polls of people who don’t pay a lot of attention to details but who find something or someone “new” to be “refreshing,” especially when the media spins inanities and ignorance into profundity.

With its illiterate, dim, confused and TV-obsessed “hero,” more than one wag has revived “Being There” in recent years as a predictor of The Trump Era. Cultures don’t degrade or revive themselves overnight. And great films have a timelessness that keeps them relevant through the ages.

Chance (Sellers) has grown up in the servants’ quarters of a posh city townhouse gone to seed, so we gather. He watches TV obsessively, changing the channel compulsively. He polishes “the old man’s” car — a 1938 Packard Eight whose whitewalls have long been flat — and tends his garden. Chance, the gardener, has been doing this and only this for all of his 50some years.

Then housekeeper Louise (Ruth Attaway, brilliantly tactless and furious), who has prepared his meals for most of his life, announces “The old man’s dead.” Chance says “I see” so inscrutably that we might confuse his confusion for solemnity and gravitas. Throughout the movie, everybody else does.

When Chance says “I understand,” he does nothing of the sort. When he notes “I’ve never been allowed out of the house,” or “I don’t read” or “I can’t sign” his name when a lawyer (the redoubtable David Clennon) shows up and questions Chance in classic legal CYA speak, he’s being literal. Not to worry, “I have no claim” Chance assures our litigation-shy lawyer. Chance is unsure of what the word means.

Eviction puts Chance on the street without even the most basic skills of survival. But his very expensive but dated tailored double-breasted suit, coat and hat speaks volumes. And “Being There” truly announces itself as one of the greatest films ever the minute Chance walks out that door and into a D.C. neighborhood that this mansion/townhouse has slowly gone to ruin within.

For eight minutes, this innocent abroad strolls the streets with their empty storefronts and litter. He stares past the urban decay to fuss over the state of the flora, asks Black female strangers he meets if they could make him his lunch and meets Black street punks who have a message for the “honky” to deliver to their rival, Raphael, with this entire odyssey set to the electronic jazz version of “Also Sprach Zarathustra” by Deodato.

No, this isn’t “2001.” It’s America in the late ’70s — as vivid a montage of struggling cities, the disadvantaged Black and Hispanic generations who prompted racist White Flight from those cities — and the power elite who cluelessly and heartlessly presided over it all.

“It’s for sure that it’s a white man’s world in America!” Louise fumes in the rundown boarding house where she and other Black domestic labor are fated to spend their retirement. Because she sees Chance on TV.

The simpleton who can’t discern reality from television, to the extent he uses his TV remote to try and change the channel from his unpleasant encounter with gang-bangers, stumbles into an accident, is rescued by the trophy wife (Shirley MacLaine) of aged, rich D.C. power broker Benjamin Rand (Melvyn Douglas). Chance the Gardener is confused for “Chauncey Gardiner,” with his every word misinterpreted and every coincidence that puts him in the orbit of Rand and the rest of the aged, white D.C. elite allowing one and all to mistake him for a behind-the-scenes shaker and mover, an inscrutable sage of the age with the ear of the powerful and their president (Jack Warden).

“Shortchanged by the Lord, and dumb as a jackass,” Louise preaches. “Look at him now!”

 Chance only knows gardening, so his answer to every question comes in horticultural or landscaping terms.

“In a garden, growth has its season,” he intones. His serenity and bearing and attire make one and all take him seriously to an absurd degree. He MUST be talking about the economy and President Bobby’s handling of stagflation, etc.

Don’t ask him his opinion of anything that isn’t planted in the ground — not politics or economics or the press.

“I do not read papers,” he confesses. “I watch TV.”

That adds to his mystique and every gaffe or confession about his limitations just adds to the “inscrutable” label newspaper editors, TV producers, pundits and senators attach to him.

Sellers anchors the film with a character whose contemplative stillness and blank-faced silences begs for others to fill the void that he is with whatever they can imagine. We see his first failed attempt at a cigar or alcoholic drink. When the lonely soon-to-be-widowed Mrs. Rand comes on to him, she has to compete with the television and misinterpret what he says about that to get any sexual satisfaction.

“I like to watch.”

MacLaine sparkles as credibly coddled and wealthy, devoted to a much older, very rich and powerful man. She’s sure “Chauncey” is related or at least knows she and Daddy Warbucks’ pals, the equally entitled Gardiners.

“We often visit their island.” Ahem.

Douglas won the best supporting actor Oscar for playing a born-rich, noblesse-oblige resistant personification of The Elite.

“The businessman of today is at the mercy of kid lawyers at the S.E.C. (Securities and Exchange Commission),” the richer-than-Midas Rand fumes. What he wouldn’t do to have a president who attends to the needs and whims of the superrich in the White House.

Warden is adorably befuddled and infuriated as a president who needs Rand’s support — that last name can’t be a coincidence — and can’t figure out who “Chauncey Gardiner” is and how to get on this new power figure’s good side.

Richard Dysart plays the personal physician to Rand, one of the few — like Clennon’s lawyer and Attaway’s housekeeper Ruth — who figures it all out and is either bemused or helpless to stop the unfolding fiction from passing through the highest portals of power.

There’s so much to take in here and so very much that — intentionally or by happenstance — seems utterly perfect all these decades later, from Sellers’ greatest performance to the America-in-winter setting and Biltmore Estate (Asheville, N.C.) location.

Ashby, who directed not just “Shampoo” and “Harold and Maude,” but “Bound for Glory,” “The Last Detail” and “Coming Home,” was the perfect filmmaker to make this satire of the sublimely ridiculous amidst the troubling dumbing down of the culture and counterculture.

Ashby was an Oscar winning editor (“In the Heat of the Night”) turned director, and his films — like those of editor-turned-director David Lean — are striking not just for the iconic images — Chance walking on water, a naive prophet who doesn’t know any better — but for the “perfectionist” editing he insisted on.

He died relatively young, at 59. And one thing I learned about him in my years as an entertainment journalist was to never mention his name to women who worked for him — Bette Midler especially.

I was moved to jot down the name of video consultant/editor Dianne Schroeder from the credits of “Being There.” She cleverly rounded up the reams of then-new commercials, public service announcements and even a pre-MTV music video of Cheech and Chong’s “Basketball Jones” for insertion into the proceedings — periodic snapshots of ’70s pop culture and consumerism, from “Mister Rogers’ Neighborhood” to “Captain Kangaroo,” sampling everything sold via TV in greater D.C. and America in general. That makes for a perfect pre-HD cathode-ray-tube snapshot of America of that era.

And then there are the hilarious and brief outtakes in the closing credits. Sellers went to his grave thinking Ashby ruined his last shot at an Oscar by breaking “the spell” the movie and his performance in it cast. We see the perfection of his utterly controlled, always-in-character acting contrasted with the inability to get through a scene cut from the film, in which he and those on set around him can’t get through a recitation of a street gang message in D.C. street argot without breaking up.

I dare say Sellers was right about Ashby’s blunder, up to a point.

But after years of movie set/movie business misbehavior where any film he didn’t make with Blake Edwards (“The Pink Panther” movies, “The Party”) was either a bomb or a debacle ruined by how difficult Sellers was to work with, I’m guessing he wasn’t all that popular with the people in the Academy of Motion Picture Arts and Sciences.

So the best actor Oscar went to Dustin Hoffman, and even he referred to “Kramer vs. Kramer” as a “soap opera.” At least Sellers won a Golden Globe.

For me, this was the movie that taught me that awards don’t matter. Great films, great performers and great performances endure even if fickle Hollywood doesn’t recognize them at the time.

“Being There” is the smartest and slyest and most perfect expression of its era, a movie that put an exclamation point on the end of perhaps the greatest decade Hollywood movies will ever know.

Rating: PG, masturbation, profanity

Cast: Peter Sellers, Shirley MacLaine, Melvyn Douglas, Jack Warden, Fran Brill, Richard Dysart and Richard Dysart, David Clennon and Ruth Attaway.

Credits: Directed by Hal Ashby, scripted by Jerzy Kosinski, based on his novel.

Running time: 2:10