Not necessarily true. If people weren't getting compensated in some way they would leave. Investment bankers work 80-120 hours per week, and they get paid as such. Same with lawyers.
How does your average Silicon Valley 60+ hour worker get extra compensation for those additional hours that are expected of him (beyond the contractually agreed 40 hours)?
Faster advancement within the company. Executives aren't in their position simply because they are smarter than everyone else. After an IQ of 120-125, intelligence is not a good predictor of success (according to Malcolm Gladwell at least). Hard work plays a role.
If you want to work a normal work week and a normal life, great. But sometimes to achieve great things you have to make sacrifices.