I thought about that often. Why are highly intelligent, passionate young activists not working into the industries they despise to change the system from within. But you're right that the system you're in changes you, corrupts you. You'd have to sacrifice a lot to climb the corporate ladder, doing things you despise, just for the chance to blow things up years, decades later. Your idealists friends would distance themselves from you. You'd have to constantly remind yourself that you're doing wrong things but that it's ok, because it is part of a bigger plan. It would be very isolating. You'd probably sacrifice your sanity for a foolish plan.
Most people think that their values come from some immanent "Self" but in reality our values mostly come from our surroundings. The same baby with the same genetics raised in Broken Arrow, Oklahoma vs. Upper West Side New York will have extremely different values, go farther than that and the difference in values is almost unrecognizable. If you or I grew up in wealthy families in ancient Greece, we would think NOT owning slaves was weird and suspicious.