VC's aren't exploiting the system. They bet their money on stuff which they can loose. How many of such bets turn out to be successful. You work hard on your one start up. Remember they are betting on many start up's at one time.
That risk deserves some reward. Eventually considering the research and decisions they need to take over time to stay alive. VC's need to work hard too.
When they make 100x more than you in an IPO, they are basically getting compensated only as much you because they lost money somewhere else.
They may get 100x more from your start up but remember they are loosing elsewhere. So in principle you both earn the same.