What Rush has going for him is that he's on the radio. Radio makes everything more palatable for me because its usually consumed in the car during a long commute. I don't care who you are: drive long enough and it gets lonely, and so even pundits are in a sense welcome if they're on AM. For this reason I've listened to more Art Blackwell and even Revered Al than I care to admit. Put the same guys on TV when I'm home with a million other things to entertain me, and these guys can all go to hell.
Colbert ate shit, too. Not much use for the smug self-affected intellectual. Like Stewart he wasn't nearly as smart as he believed himself to be.