What do you mean by 'cost of influence'? If I don't want influence, is it optional?
Every political system has patrician and plebeian tracks. In America, the former can be bought (versus solely inherited). Being a politically-active patrician in New York involves an expensive list of patronage. That’s where the power players are, and that’s where you’ll cut casual deals.
It’s optional. And it’s different from civic responsibility. But unless you think the status quo is hunky dory, you’re going to want to change things, and the cost of access varies geographically.