As long-running multicam sitcoms “Last Man Standing” and “Mom” wrap up their runs this month, it might very well also be the end of another chapter in TV history. Even as the broadcast networks prepare to order a crop of new series and announce their fall schedules next week, the idea that a new sitcom might make it to the once-vaunted threshold of 100 episodes — let alone more than that — seems antiquated.

For one thing, the big-bucks syndication marketplace of yore is mostly gone, making that four-season, 100-episode mark less necessary to reach. (Warner Bros. TV’s “Young Sheldon” was recently sold into syndication with 83 episodes, for example.) And in this age of primetime erosion and viewer migration to the streaming world, season orders are short — usually 10 episodes, a far cry from the once-common 22- or 24-episode count — and many comedies are wrapping up within a few years of launch. Or they take long hiatuses, keeping their episodic tally to a minimum.

While the two longest-running scripted series in U.S. history are still on the air (“The Simpsons” and “Law & Order: SVU”), as the comedy stalwarts of primetime disappear, it’s unclear whether new ones will ever match that longevity. “Last Man Standing” exits on May 20 with 194 episodes (over nine seasons and on two networks), while “Mom” ends its run on May 13 with 170 episodes over eight seasons.

“We put a lot of pressure on ourselves to get this one right,” “Last Man Standing” executive producer Kevin Abbott says of the finale. “I mean, nine years in, there’s not going to be a whole lot of comedies anymore that go that long in the new streaming era.”

Former Paramount Network TV president Garry Hart, who oversaw several long-running comedies during his tenure there, including “Frasier” (264 episodes over 11 seasons), is more optimistic that audiences and conglomerates will still hunger for those long-lasting series. “Historically TV has always had cycles,” Hart says, “and funny never goes out of favor.”

“Frasier” sure hasn’t, which is why Paramount Plus is bringing the character, first seen on “Cheers,” back for another go-round. Hart is bullish: “I have my fingers crossed for a nice long run with chapter three of Frasier Crane.”

And yet recent hit series that seemed poised to go longer but didn’t include NBC’s “Superstore,” which was retired this year after 113 episodes and six seasons, just barely over that 100 mark. Long-running comedies still on the air include ABC’s “The Goldbergs” and “Black-ish,” plus NBC’s “Brooklyn Nine-Nine.”

Then there’s the case of FX’s “It’s Always Sunny in Philadelphia,” which has made it to 154 episodes, despite rarely producing more than 10 a year, because it’s been on for 14 seasons — and it’s slated to continue for at least four more.

“When something works, and people are still willing to continue to make it, I think it can continue on,” says “Sunny” star and executive producer Rob McElhenney, who remembers advice he once received from “Curb Your Enthusiasm” creator and star Larry David. “He said to me, don’t ever stop. Never do a last episode ever. Don’t ever stop doing it; just keep doing it. And you realize, that’s what he’s doing with ‘Curb’: He’s not stopping — he might take off for four years, and then it’ll come back and do another season. So I don’t know, maybe I’ll take his advice.”