Because "human capital" (no matter how dehumanizing it sounds) is the best one, people with money want to invest in people with great minds. Otherwise investors

Because "human capital" (no matter how dehumanizing it sounds) is the best one, people with money want to invest in people with great minds. Otherwise investors's money will evaporate because of for example inflation. Also, throwing couple of millions into a growing company means "i want to be part of it and take back some revenue hoping it'll be huge".