Is Dave Letterman just an old man who complains about everything?

He used to be a visionary, and an innovator. But he's being the same
show now for 20 years, and he's not any funnier.

He seems to be a lot like Regis, he just seems to complain about
anything. The only difference is that Regis completely alienates his
audience by complaining about rich people problems, and constantly
name-dropping. Dave just seems to complain about anything.