The thing about Seinfeld and other comedians who aren't as popular anymore is that they blame the audience for not liking their material. Tastes change over time. The comedian either needs to change their act or live with the consequences that people aren't going to like their material as much.
Rodney Dangerfield was a great comic for his time. If someone tried to tell the same jokes today, I don't think he'd get very far. That's not the fault of the audience. It's the fault of the comedian. No one owes you a laugh.