I think a big part of the ability of these shady companies pulling the brightest minds away from more clearly beneficial fields is that important flavors of ideology necessary to motivate people to take less lucrative work have been stripped from "business". There's a lot fewer appeals to art, history, cultural stewardship, or empire-building present in things like transportation, medicine, construction, etc. than there were in the past. Any flavor of "for the glory of God/the nation/the People/the Art" etc. is pretty effectively stripped out of American business, and I think that's the only kind of thing that would motivate someone who could make $250k in Adware to make $100k in something else.
People are now very well-trained to look out for their own bottom line, and take jobs accordingly.