The balance is that if the park doesn't let enough people in, the people stop supporting the park. America is democratic. Parks are not protected by royal proclamation. If the park is inaccessible then people don't visit. Then they don't care about it. Then one day someone wants to drill for oil in the park, and nobody cares enough to vote that down.
I really don't mind the car-camping crowd. They stay inside their gravel circles and don't impact the real wilderness much. But come time to vote they will always far outnumber the dedicated rock climbers. I want the car campers on my side. If that means giving them their parking spots then so be it.