I think it's because a lot of his humor is self-deprecating, so many of his jokes are "on" him.
> “I’ve got maybe 10 years to ladle the butter into a jar for my kids and then die”
I think it started with him saying his career would be over in a year. Last year when I saw him he said "two, maybe three years tops" before people would forget about him, and now I guess he feels a little more confident that he'll be sticking around for a while.