When it debuted, “Boardwalk Empire” looked like the answer to HBO’s prayers.

Another mob series with a glittering pedigree, including Martin Scorsese, who practically defined post-“The Godfather” crime movies; and “The Sopranos” alums Terence Winter and Steve Buscemi. A barrel full of Emmy nominations and a Golden Globe award quickly followed.

Yet despite early awards heat and critical accolades, the pay-TV paean to Atlantic City didn’t fully cash in. What HBO programming president Michael Lombardo dubbed “one of the most superb ensemble casts of any television show I can think of” nabbed eight Emmys its freshman year (one short of “The West Wing’s” record), but lost best drama to “Mad Men,” produced by Winter’s former “Sopranos” colleague Matthew Weiner.

“Boardwalk” has remained a critical favorite. Yet with the crush of prestigious new programs in the ensuing years, the show slipped off the best-series ballot the past two seasons.

“We’re not the new kids anymore,” Winter said, not long before the show wrapped principal photography on its fifth and final season in late August. “The more time passes, the more new shows get introduced and steal your thunder. People’s focus shifts to that.”

Jake Chessum for Variety Jake Chessum for Variety

Indeed, if “Boardwalk” at one point appeared the obvious heir to “The Sopranos” — the series HBO had labored to find — in terms of popularity at least, that mantle has passed to another drama about feuding families and the exercise of power: “Game of Thrones,” which actually surpassed Tony Soprano’s gang in aggregated ratings during its fourth season. (The statistic warrants an asterisk, given that the population has grown, but it’s an accomplishment nevertheless.)

All that serves as backstory as “Boardwalk Empire” charges to the finish line, adhering to Winter’s timetable on when the show’s “last call” should be. And unlike a lot of programs faced with the daunting task of brewing up a satisfying climax, this one, rooted in early 20th-century history, and focusing on bootlegger Nucky Thompson (Buscemi), came with a logical expiration date: the repeal of Prohibition, making all the repercussions related to trafficking in illegal booze a moot point.

“In my very early conversations with Terry Winter, we discussed the idea that first and foremost this was Nucky’s story, so the end point would be dictated by what was happening with him,” Scorsese said via email. “Because the Prohibition years specifically provide the backdrop to that story, tying the repeal in to the conclusion was almost a fait accompli.”

SEE ALSO: New York City is a Key Plank for ‘Boardwalk Empire’s’ Attention to Detail

In a sense, “Boardwalk Empire’s” gaudy creative auspices became a pair of velvet handcuffs. With all the marquee talent involved — and a pilot reported to have cost in the $20 million range, including a dazzling multimillion-dollar replica of Atlantic City’s boardwalk circa the 1920s — it could go only one of two ways: Be very, very good, or a major disappointment.

If all new TV shows are a gamble, more than most, “Boardwalk Empire” appeared to be stacking the deck.

“Audiences like to discover shows sometimes,” said Lombardo. “And I think ‘Boardwalk Empire’ — that’s a big promise. This came with very high expectations. Martin Scorsese directing a pilot? Mobsters? Come on. ‘Boardwalk’ came out with guns blazing.”

Those involved with the show insisted they didn’t feel the burden, or at least, were able to shield themselves from it. As for qualms about venturing into territory so sure to draw comparisons with some of the best movies and TV ever made, they kept returning to the same general thought: Working on “Boardwalk” was an offer they simply couldn’t refuse.

Jake Chessum for Variety Jake Chessum for Variety

“I don’t know that I would have chosen to do a mob show immediately, but it was too much to resist,” Winter explained. “They gave me the book. They said, ‘See if there’s a series in there, and oh, by the way, Martin Scorsese’s attached.’”

Buscemi echoed feeling the draw of collaborating with that level of talent. “Knowing that Terry Winter was the main writer, and the pilot was being directed by Marty, that would be enough to do it,” said the star. Besides, he added, “You just can’t look bad in those suits. It really was the role of a lifetime.”

Scorsese said the question of expectations or comparisons — to his own work, or anybody else’s — never factored in to his desire to do the project.

SEE ALSO: Terence Winter Touts a Homefield Advantage for ‘Boardwalk Empire’

“For me, character and story are paramount. If a compelling tale happens to be told within the context of a genre I’ve worked in before, that’s fine,” he said. “The chance to do it for television was actually an incentive. I’d long been interested in longform storytelling, and a tale of this magnitude required dozens of hours to do it justice.”

Nor was Scorsese an absentee landlord, as many feature directors are after shooting a pilot and nabbing executive producer credit. Winter said the two spoke regularly, with Scorsese weighing in on casting, watching cuts and dailies, reading scripts and offering notes.

“He has an ability to keep stuff in his head that I’ve never seen with anybody,” Winter marveled.

The series got its start with a book written by then-first-time author Nelson Johnson — a Superior Court Judge in Atlantic County — which chronicled the city’s history and its colorful denizens over decades. Once the work was optioned, Winter zeroed in on the ’20s, seeing that as a relatively fresh era given the time lapse since “The Untouchables” TV series and Brian DePalma’s theatrical version.

Buscemi’s Enoch “Nucky” Thompson is a slightly torqued version of the book’s real-life political boss Nucky Johnson. Along the way, his circle has included everyone from members of the Harding administration to Joseph Kennedy, as well as mobsters like Al Capone, Lucky Luciano, Meyer Lansky, George Remus (who really did talk about himself in the third person) and Arnold Rothstein.

The show also tackled the African-American experience through the character of Chalky White, played by Michael Kenneth Williams, who has completed a second five-year tour of duty on a prestigious HBO drama, having starred as Omar in the acclaimed series “The Wire.”

Jake Chessum for Variety Jake Chessum for Variety

But the two experiences, reported Williams, couldn’t possibly have been more different.

“We shot ‘The Wire’ for scraps. They threw a shitload of money at ‘Boardwalk.’ They had to,” he said, adding that just coming onto the set “felt like you walked through a time machine.”

There are various theories as to why “Boardwalk” blazed hot and then cooled, at least on the awards circuit, while some dramatic contemporaries kept earning top nominations year after year. Perhaps the show’s grim, occasionally gruesome content — from incest to autoerotic asphyxiation to severed ears — is simply too much for some viewers (and especially, Television Academy members) to handle.

But most agree that they have been content to focus on the work, and that comparisons to “The Sopranos” — while perhaps inevitable — were unrealistic.

“I tried not to pay attention to the hoopla,” Buscemi said. “I put ‘The Sopranos’ in its own category. It’s ‘The Sopranos,’ and there’s nothing else like it. I don’t think anyone had any expectations of duplicating that phenomenon.”

Much of the focus now is on the final season, and fairly or not, how “Boardwalk” will be remembered will be tied in part to how viewers respond to the finale.

On that point, few programs have been more polarizing than “The Sopranos,” although Winter, having worked on the show, said he was surprised by the negative reaction to the final episode (“I did not anticipate how that would be received. I loved it”), and Lombardo insisted the fact that people are still arguing its merits qualifies as an endorsement.

“We’ve debated it for 10 years, but you know, that was the perfect ending,” he said of Tony’s fade to black. “It’s hard to fulfill everybody’s expectations, and I don’t think that’s what anybody should set out to do.”

For the cast and crew, “Boardwalk Empire’s” finish still hasn’t entirely sunk in. Williams said the experience “exposed me to a whole different audience,” citing as evidence that “little old Italian ladies walk up to me and go, ‘Chalky!’ ”

Co-star Gretchen Mol said cast members were always keenly aware they might not survive the full run — especially after the actor who played her son, Michael Pitt, checked out relatively early.

Moreover, because Mol played opposite different actors every season — including Pitt, Bobby Cannavale and Ron Livingston — the corner of “Boardwalk” she occupied was constantly changing, an experience that proved both heady and challenging. “Each season felt like a whole new thing,” she said. “This has been a seminal experience. It’s going to be hard to top it.”

For Winter, attention now turns to an eagerly anticipated rock ’n’ roll drama — also for HBO, and also with Scorsese. Asked about whether he needed time to decompress, he laughed and said, “I don’t vacation very well.”

Coupled with the end of “True Blood” after seven seasons, HBO’s Lombardo conceded, “It’s terrifying to be walking away from two shows this year that have such big ratings for us,” but added that the network never wants to be in the business of forcing shows to stay on the air beyond the point producers believe it’s time to wrap them up.

“The most important thing is that the creators feel they got to end the story in a way they felt was appropriate,” Lombardo said. “It started with Terry, it ends with Terry.”

And given how series finales have become such a fundamental part of the serialized life cycle, the last word on “Boardwalk’s” legacy might come down to that final spin of the bottle.