Is this actually true? (note - I don't know) My understanding is most VC firms aren't successful. Just a few are.
I've thought about writing a post almost identical to the OP and came to your same conclusion: "At the end of the day they have the money". The other harsh reality is that VCs are no different than the enterprise companies of today's world...they are all about reducing risks at scale. One of their scariest risks is failing to instill confidence in their clients. For example, if the market dictates that the hottest thing right now is photo sharing, you better be damn sure that a VC is going to invest in a photo sharing app. The VC is going to say "Dear client, we aren't going to invest in the next big photo sharing app, even though all of the analyst say its the next big thing. Instead we're investing in 21st century pig farms!" The client will say "but what about Instagram!" No matter how risky you personally believe it is (for example - photo sharing apps have no revenues) the market still is throwing money at it (i.e. Instagram).
So, conclusion - I blame media hyperbole and people's natural biases, not VCs on the amount of funding put into "good" startups.