Jay Leno and Johnny Carson

Accomplishing this “almost mythic rite of passage”  was the entire premise of Martin Scorsese’s pitch-dark 1983 classic The King of Comedy, about an unfunny stand-up who breaks numerous federal statutes just to get “couch time.”

Then one night, when Johnny said his last goodbye, that career arc, that “business model,” that fantasy every American comedian had nurtured since they were one of those kids sneaking downstairs, went poof.

Carson’s replacement, Jay Leno, was no Johnny, and many other stand-ups never let him forget it. In comedy circles, Leno’s name is still a byword for “hack” and “sell out,” even “double crosser.”

What you’d think would be “inside showbiz” gossip of the most tedious kind”€”the Tonight Show host succession saga”€”became a bestselling book, an award-winning HBO movie, and the stuff of indelible pop-culture legend: nice, warm, mainstream (but underhanded) Leno v. mean, cold, edgy (but honorable) David Letterman, who’d always presumed he’d inherit the job.

Fast-forward more than two decades: Jimmy Fallon was anointed Leno’s successor without a moment’s drama. And Leno’s final farewell shows won’t be “appointment television,” like Carson’s. (Johnny’s coincided with my stint at a TV-free mountaintop writers’ retreat; before I boarded my plane, I made a friend vow to stay up and videotape every one.)

Today’s comics can build their own couch”€”hell, their own desk”€”thanks to YouTube and no-brainer podcasting platforms.

Many of those stand-ups have never forgiven Leno for supposedly not giving them enough “couch time;” for being a hardworking, once-married, sober, non-smoking, non-gambling square, the un-Belushi; for “stealing” Letterman’s rightful throne.

It all seems ridiculous now that, frankly, nobody “needs” The Tonight Show. (Except maybe Burbank.)

Especially not Leno, who’s continued to work on the road while pocketing his $15 million per year salary from the “snakes” at NBC and spending much of his “Vegas money” on his real passion: his breathtaking car collection.

The high price of gas aside, Jay Leno picked the perfect moment to abdicate from what used to be television’s most coveted job. No surprise. He’s a pro, and in comedy, timing is everything.