You have to consider the risk/illiquidity that's taken on to achieve that return.

It's my understanding that VC works in a manner similar to PE, where investors are given their returns when the entire fund they invest in is run down. Each fund has a vintage, so if you invest in the 2006 fund you might get paid back 7 years from then in 2013, that's kind of a long time.

For a liquid asset class to compare to, equities have done something like 6-6.5% real historically.