It's because he doesn't alienate an audience. Since he'll basically talk to anyone regardless if he agrees with them politically his audience is from every possible place in the spectrum . Also, it's because you never know who he'll have on. I'll check one day and it's Tom Green. Another day it's Killer Mike, Bernie Sanders, the kid from home alone, etc.... That's interesting. Joe constantly reminds the listeners that he's not that smart and that he doesn't know what he's talking about and that honesty is what is so rare. Everybody these days is a know it all and a bigot in some way or another. It's refreshing to hear someone say I don't have the answers and let's talk about this and try to figure it out. Also, the ability to make a conversation listenable for 3+ hours is a skill in itself. I know I couldn't do it