I can see why Letterman retired. His list is silly at best.
Letterman’s “retirement” wasn’t completely voluntary. Before announcing his departure, Craig Ferguson left “The Late, Late Show,” which was produced by Letterman’s production company. CBS announced that it would assume full control of the 12:30 timeslot with Ferguson’s departure, meaning that Letterman would have no control over the program—and lose his share of the profits as well.
Additionally, Letterman’s contract was up at CBS and by all indications, he would have taken a pay cut if he decided to re-up. The network talked at great length about how proud they were of “The Late Show,” and the critical praise it received, but that couldn’t obscure a rather painful fact: Jay Leno had been kicking Letterman’s ass in the ratings for years, generating millions more in profit for NBC and when Leno retired, Jimmy Fallon picked up where he left off. Even Letterman could read the handwriting on the wall.
When Johnny Carson left the Tonight Show, he only made one more TV appearance—a brief walk-on with Letterman years later. Unfortunately, it doesn’t look like Dave will follow Carson’s example. Watch for him to pop up with greater frequency in the months and years to come.