He did jump the shark and became very bitter, probably after his office affairs and attempted extortion became public.
It seemed to me that he became bitter late in life and his comedy suffered the same way that George Carlin's did after Carlin's first wife died from cancer.
-PJ
Exactly. I used to be a big fan of Letterman....back when he was funny. That was the 1980s through the early to mid 90s.
Fast forward about a decade later and was calling him “Bitterman”. He was. He was just downright bitter - all the time.
Bitter isn’t funny or entertaining.