I think it's something else. I think both parties protect incumbents who carry their water. For these partners in crime, the party effectively shuts out any competition.
When you displease the party, you are 'primaried'. The party pulls in favors from the media for stories that follow their preferred narrative, just as they did in the Clinton / Sanders case.
People are stupid enough to pull a lever based on nothing more than name recognition. Little thought goes into what the person did to cause you to recognize their name.
I think most US elected officials are criminals who deserve jail time. It's like the Cosa Nostra. Some, I'm sure, have committed treason and deserve execution.
This is American politics currently. The media feeding frenzy on Trump right now is at a crazed fever pitch largely because of the media/DNC collusion, but certainly Trump's actions give them plenty of fodder.