Okay, you go ahead and bet on the companies that will pay you a 10x return in ten years and I'll take the 2x return in two months. Will Instagram even exist in 10 years? Who knows? I wouldn't bet on it.
BTW, you're absolutely right. The 2x return extrapolates to a return of trillions of dollars over ten years, so there really is no contest at all.
It doesn't matter if you run a hedge fund, a VC fund, or a trust fund. A 2x return is a 2x return, and anybody would take it any day. Anybody who wouldn't has no business working in finance. Just because you assign a ten-year time frame to your portfolio does not diminish the return on that investment, so the return on your $50mm is 2x, not 1.1x.
If you guide your investment strategy based only upon what you hope will happen in the best-case scenario and look down upon investments that double your investment, you're making a mistake. The only reason they need a 10x return on their winners is because at least nine other bets are going to lose. Any win adds value to the fund. As a fund manager would you rather the $50 million have been plowed into a business that returned 0% which is what you expect to have happen ~90% of the time? Do you understand why criticizing this investment makes no sense? You're comparing a great investment to the few investments that turn out to be astronomically fantastic instead of the vast majority that lose money.