Powerful families are chummy with other powerful people because power ends up being the most important status symbol, and ideology can hide behind it.
It's basically the reason that orthodox Republican economic policy can even exist. It's terribly debunked theory, but because the messengers are WSJ op-ed writers that went to fancy schools and wear bow ties to work, their view "couldn't possibly be just wrong".
There was some polls recently that showed that when asked about GOP tax plans, people refused to believe that the pollsters were even telling the truth on the facts, because it was so absurd. Of course there wouldn't be a tax break for private jet maintenance!
But politicians believe their friends, just like we all do. It's the base of "keep politics out of X".