Well, it's free advertising; they'll both make money on any publicity. Kind of like pro wrestling.
Unfortunately, listeners take it seriously, and we do have folks acting out. And millions more are disenchanted with America because these guys tell us that our fellow citizens are loathsome folks who want to destroy all "decent" people.
In the 50's we were told there was a secret commie on every block, who was working for the Russians. Media talking heads and Congressmen said ridiculous things and made ridiculous charges of "UnAmericanism". People were reluctant to speak up, because they would likely turn on YOU if you said anything. These guys are the new generation. Everyone has free mouth, but innocent people do get hurt as we watch this crap.
Supposedly we're better educated now, but it seems worse, not better. People are afraid of Limbaugh and Sharpden, and they know it.