The truth is that regardless of how well put together a firm is, break-out success is a crap shoot. A VC strategy that maximizes potential revenue (by heavy due diligence) is almost always going to end up with lower actual revenue than a VC strategy that attempts to maximize actual revenue, by having a larger, diversified basket. If the terms of the initial funding give the VC first crack/options for later rounds, all the better.
He argues since returns are distributed by a power law, more due diligence and fewer invests make more sense for VCs.