Just to throw another point into the discussion - to some extent, brain power is fungible. I say this speaking as someone who has a clear and ongoing choice between academia and industry. However, currently, academia is a world of hurt for most post-docs (several articles on the topic have passed HN, they're out there if you're interested). So, maybe the reason people aren't curing cancer is because curing cancer doesn't pay even half as well as selling ads, and it comes with a whole lot of other issues (short term contracts, high pressure, long hours, etc). I really believe that if there was a higher financial incentive / more funding support for science, we could keep more of the brightest, and things would progress faster. But in a recession, we get austerity measures, and half the kids move into strategy consulting / finance. Anyway, that's another conversation. </rant>