It can be easy to forget quite how big a deal, in its early going, “Mr. Robot” was.

It eventually became, fairly enough, a hallmark for narrative and directorial excess. But the series, about Elliot, a hacker attempting to remake America, had the real-life effect of remaking the USA Network, shifting the cabler conclusively away from its previous model of sunny workplace dramedy. Its broader implications included the launches of executive producer Sam Esmail, with Amazon’s “Homecoming” and USA’s forthcoming “Briarpatch” to his credit, and star Rami Malek (who won an Emmy for his recessive, inward “Mr. Robot” performance and an Oscar for its opposite in “Bohemian Rhapsody”). And its conceit, that the world is governed by entities interested in seeding chaos for their own benefit, has seemed more urgent since the show’s 2015 premiere. The near-perfect first season had the right talent and the right timing.

But subsequent seasons’ refusal to consider the world outside Elliot’s head diminished its viewership and reputation. So it is that Season 4, the show’s last, takes us back to 2015, the year in which its characters are still living — and back to a time when “Mr. Robot” was a necessary watch. It cuts its way to success, finding a leaner and more propulsive drama underneath indulgences. Told with typical confidence and flair but with a new note of humility too, the season, at least in its early stages, represents a high note for one of the decade’s signature prestige dramas.

The season, Esmail has said, is to take place entirely over the 2015 holiday period — either a richly symbolic time, sitting on the precipice of a historic election year, or not. No one in this story seems to care who the president is, though madness obviously tends to redound to the benefit of Whiterose (BD Wong), “Mr. Robot’s” world-conquering corporatist. Elliot’s previous heroics — canceling global debt in the first season — ended up only helping Whiterose consolidate power.

Indeed, one of the show’s minor-key revelations, one too often drowned out by flashier elements, is how easy it is to become a useful idiot in the attempt to do good. In this final season, Elliot’s attempts to set right that which he had unsettled are assisted by Phillip Price (Michael Cristofer), a CEO beholden to Whiterose who realizes, too late, ambition is not itself virtue. (For a series that wears its obvious debts to “Fight Club” proudly, “Mr. Robot” is, more than ever, refreshingly un-Nietzchean, believing less in its heroes as singular forces than as fallible creatures who can only succeed through collaboration.) Characters at the margins of the story help suffuse the series’ closing hours with pain and regret over failed idealism: FBI Agent Dominique DiPierro (Grace Gummer, never better) is forced past a moral gray zone into abetting brutality as she’s blackmailed by a foot soldier of evil (Ashlie Atkinson) whose banal facelessness is the point. Early in the show’s going, Elliot and others wore masks to carry out their culture-altering mission; the forces ready to pick up the pieces in service of cruelty, we realize now, wore the pleasantly banal faces not just of corporate officers but of blandly avaricious American life.

It’s powerful, and with limited precedent, to see so much of the world outside Elliot. Esmail’s insistence on focusing inward — including and especially on Elliot’s relationship with his alter personality, Mr. Robot (Christian Slater) — had, in the seasons after the series’ explosive launch, flattened a gifted ensemble. They served a purpose for Elliot or for the story, then exited the stage when the purpose was fulfilled. This season gives showcase acting moments to Portia Doubleday’s Angela, a former corporate serf reckless in her emboldened passion to destroy Whiterose; Carly Chaikin’s Darlene, animated less by vengeance or revolutionary fervor than by desire for a normalcy that will never arrive; and Martin Wallström’s Tyrell Wellick, a man brought low by his inability to envision revolutionary change without himself at the center.

Such moments are possible because we see them with a sort of final clarity, as though, in his last moments of this story, Esmail is growing weary of devices. (Such a case is made literally by a meta moment at the end of the season’s first episode, one that suggests Esmail now wishes to wrest Elliot out of the story.) The dialing-back of Elliot — still the protagonist, but no longer the pivot point for every element of the show — represents a trust in Malek, perhaps, to remain in memory even when not on screen. It also belatedly acknowledges just how much the show has held in reserve. “Mr. Robot’s” flash had manifested itself in, say, a third-season episode following Elliot in what appeared to be one continuous take — showmanship for its sake that necessarily excluded huge swaths of the story. Esmail wields his camera confidently as ever, and the fourth season is muscular filmmaking (and, incidentally, among the best shooting of New York as setting and as overwhelming physical force I’ve seen). But it’s not filmmaking that swallows the story.

Perhaps Esmail learned something from “Homecoming” — the 30-minute, closed-ended drama whose very constraints helped make it a powerful success. Maybe, too, a show that hasn’t literally left 2015 is animated by a mournful understanding of what lies beyond. There’s a hauntedness that owes a bit to the wistfulness of anything set over Christmas, much to the performances of Malek and others, and still more to the fact that our heroes have endured defeat so far and await it in the future. Having already led a people’s revolution and discovered that it cannot end any other way but by enriching the world’s worst monsters, Elliot and company are forced to work on their own. Whether they succeed or fail — and any success, against such arrayed forces, can only be conditional — they’ve learned just how hollow it is to take down power structures, and how easily new ones spring up in their place. It’s a lesson, perhaps, that could not have borne being told at greater length. But say this for a show whose wending path toward a melancholy but true sense of itself has arrived, satisfyingly, at this closing statement: I watched the first bit of “Mr. Robot’s” endgame wishing, for the first time since that long-ago year of 2015, that I could have more.

“Mr. Robot” (season 4). USA. Oct. 6. 13 episodes (five screened for review)

Cast: Rami Malek, Christian Slater, Portia Doubleday, Carly Chaikin, Martin Wallström, Grace Gummer, Michael Cristofer, BD Wong, Ashlie Atkinson

Executive producers: Sam Esmail, Chad Hamilton, Steve Golin, Kyle Bradstreet