The superwealthy also control the Democrats, but to a lesser degree. Democrats will at least take some stand to fight for things that help the poor and the middle class on one hand, even if they pat the backs of the wealthy with the other hand.
The rhetoric of the Republicans is economically sound? I'm sorry, but when your stated objective is to bring the fiscal house back in order and then you reject massive spending cuts you want because it had pretty modest spending increases to go with it, your rhetoric--and decision making--is not "sound" at all. It's downright insane. The Republicans could not even accept near-total victory from the capitulating Democrats simply because it wasn't absolute victory like their newfound inflexible ideology demands, and so they knowingly and deliberately give up on a huge victory. That is absolutely crazy, but that is also what happens when you sign away your ability to make good decisions in exchange for power like the Republicans did to the Tea Party.