Tom Wheeler had been a telecom CEO and lobbyist prior to running the FCC. He turned out OK, solidly reining in the industry he had worked for. He knew what to watch out for, and didn't need to rely on lobbyists to explain things to him.

So it works. Integrity and patriotism matter of course. Diversifying investments prior to taking office would help reduce temptation.

Assuming that anyone who works for GS, or banking in general, are homogenous in morals and ethics and ability is equally delusional.