Notwithstanding the fact that investors look to buy low and sell high too, the point here is incorrect.
Venture capitalists, like many in financial services, are not really traders or investors. Sure, they might trade and/or invest, but their primary function is to raise capital that they can siphon fees from.
A 2% annual fee on committed capital on a $500 million fund that has an expected life of at least 10 years will produce $100 million or more in fees for a venture capital firm over its lifetime. Add a new, larger fund every few years (assuming you don't blow an earlier fund up) and you can see that the 20% carry, while potentially very significant, is really just icing on the cake.
Anybody who really wants to succeed as a venture capitalist should understand this. Incidentally, when you recognize that the limited partner side of the equation is more important than the startup side of the equation, it's not surprising that venture capital has a herd mentality and there are few true cowboys making bold bets. There is little to no incentive to stray too far from the pack.