As the “Friends” cast sheds one last tear — and cashes in one more check — countless retrospectives will undoubtedly bill the retiring sitcom as one of the greatest in TV history.

And they’ll be right.

But there’s one legacy those gushy reminiscences and sentimental recaps probably won’t touch: The megasuccess of “Friends” nearly killed the sitcom genre.

Wait — Ross and Rachel? Central Perk? “I’ll Be There For You”? Didn’t “Friends” get young viewers excited about sitcoms?

The series made the sitcom cool again for a generation turned off by the treacly emotion of “Full House” and “Blossom.” But, as they’re wont to do, TV execs pounced on that fervor and got greedy.

The webs threw on countless shows that looked, smelled and felt a whole lot like “Friends” — but without the strong writing and cast, souring many viewers on sitcoms as a whole.

Meanwhile, looking to create the next “Friends,” studios and nets went crazy for any scribe or producer connected to the show (or anyone with a “Friends” writing style), signing too many rich overall pacts that didn’t pay off.

Shows like “Friends” and “ER” also gave Warner Bros. TV tremendous leverage over NBC, just as the nets were moving toward more in-house production — a move that perhaps limited their shots at stumbling upon the next comedic hit.

” ‘Friends’ was a game changer, and the last sitcom to be that,” says CBS chairman-CEO Leslie Moonves, who ran Warner Bros. TV when the show first hit the airwaves.

“There are few shows in this last generation with the significance of a ‘Friends.’ It changed the business.”

The success of “Friends” came along just as the TV industry was going through its most dramatic upheaval since the advent of color.

Viewers, particularly young ones, had just started drifting to cable in droves. But something jaw-dropping happened in fall 1994: Two new shows, “Friends” and “ER,” exploded out of the box.

Both series attracted scores of those desirable upscale young viewers, and their casts looked like the kind of audience that media buyers salivated over.

In other words, they didn’t just want to sell a show featuring Ross, Rachel, Joey, Chandler, Monica and Phoebe — they wanted to sell to Ross, Rachel, Joey, Chandler, Monica and Phoebe.

Before “Friends,” network and ad execs were still measuring success by household ratings. After “Friends,” it was almost exclusively about adults 18-49.

“Advertisers saw that demo as a very appealing audience that had a great deal of disposable income,” says Warner Bros. TV exec VP Craig Hunegs. “They were ripe for the picking.”

It’s no surprise, then, that network execs, struggling to find a lifeboat, looked to the “Friends” formula to stay afloat.

But the networks nearly drowned in a pool of their own “Friends” clones. And the sitcom biz is still recovering from the race to gorge viewers with every imaginable twist on “the hip young pals living in the big city” concept.

“Every other network had Nielsen envy,” says former NBC Entertainment prexy Warren Littlefield. “It became the benchmark for where you wanted to play. They saw such a huge, pure 18-49 delivery, it was monstrous. Everyone said, ‘Why don’t we have that?’ ”

ABC took the most drastic step, tossing out its old formula and hiring the NBC exec who helped develop “Friends,” Jamie Tarses, to remake the Alphabet into a home for hip, urban series. The network quickly abandoned middle-of-the-road family shows like “Home Improvement” in favor of young-adult laffers like “Drew Carey Show” and “Two Guys, a Girl and a Pizza Place.”

And looking to catch lightning in a bottle twice, NBC’s Thursday night lineup became a revolving door of shows that looked suspiciously like “Friends.”

Even “Friends” exec producer Bright/Kaufman/Crane copied itself (to lesser success), coming up with the Peacock laffers “Veronica’s Closet” and “Jesse.”

Meanwhile, to satiate that hunger for a “Friends”-style hit, networks and studios began bidding up the price to sign young, hip writers to overall deals. Scribes who could boast a “Friends” credit suddenly found themselves collecting seven-figure paydays to develop sitcoms.

Suddenly, writers with short resumes were running their own shows. The talent pool thinned out, as a barrage of sitcoms hit the schedules in the late 1990s.

“Everyone wanted to sign a ‘Friends’ writer, and everyone wanted one of those signature shows,” Littlefield says. “Some shows got on the air, but I can’t remember anything that stuck.

“They were chasing the elusive next ‘Friends’ instead of identifying a unique space that could be occupied the way ‘Friends’ did,” he adds.

And as a studio, Warner Bros. was able to extract time period guarantees and hefty license fee boosts from NBC.

Those moves played a role in pushing NBC toward scheduling more in-studio product for a time. “Will & Grace” worked, but most other NBC-owned product probably stayed on longer than it should, keeping the net from adding other potential smash sitcoms.

The result of all this?

ABC continued its downward slide and eventually gave up the young-adult ghost to recapture its old identity. NBC saw its comedy fortunes diminish, as shows like “Union Square” and “Coupling” didn’t live up to the “Must See TV” moniker. Peacock now just airs two sitcoms on Thursday night, where its four-laffer block used to dominate.

Meanwhile, the industry’s super-rich overall deals yielded little of note, more or less collapsing that business. Overall deals, thrown around like candy a few years ago, are now a rare commodity.

But most importantly, viewers said “enough.” They turned to franchise dramas (“CSI,” “Law & Order” and their spinoffs) and reality TV, and virtually gave up on yuks.

To be fair, the pipeline didn’t completely run dry post-“Friends.” Shows like “Everybody Loves Raymond,” “Will & Grace” and “Malcolm in the Middle” prove that hits are still possible.

But they’re the exception to the rule. Network execs have grown frustrated waiting for the long-predicted rebirth of the sitcom. Even quality shows that promise to reinvigorate the form, such as Fox’s “Arrested Development,” can’t catch a break.

In a weird way, the collapse of the sitcom genre could be considered a pretty strong compliment to the cast and crew of “Friends.”

It’s easy to join the “Friends” backlash brigade, but hard to deny the show’s cultural impact. And at its height, “Friends” lived up to the hype.

“The attempt to duplicate the urban ensemble, the upscale milieu of ‘Friends’ didn’t yield much success, and I think that’s a testament to the quality of ‘Friends,’ ” says Universal TV topper David Kissinger. ” ‘Friends’ has that fantastic alignment of a seamless cast without any weak links — and great writing. That’s the hardest thing in the world to duplicate.”

Ultimately, viewers today simply expect more from their sitcoms than they did in the ’80s and ’90s.

“When you’re comparing things to ‘Friends,’ ‘Frasier’ and ‘Sex and the City,’ it’s harder for things to succeed,” says NBC Entertainment-News-Cable Group prexy Jeff Zucker. ” ‘Friends’ raised the bar for every comedy that followed it, and very few even came close to it.”

It may even take “Friends” leaving the air for the sitcom to find new life on its own. No one — even Zucker, who calls it “a once in a decade kind of show” — believes the genre will be dead for long.

“I don’t think the 1990s was the last great sitcom ride,” Hunegs says. “And I don’t think ‘Friends’ will be the last great or really valuable sitcom.”