Two things on that. Stern and Conan have completely different audiences, and very different situations, so they're not even comparable. And while the move away from terrestrial radio might have benefited his fans, can anyone argue that Stern's exposure hasn't taken a dramatic hit?
I mean, when I was a kid, he was The King of All Media. There was Howard Stern and then there was everyone else. Now he's just some old guy on that satellite radio service your parents' pay for (probably in their Prius or other overpiced vehicle).