One has to believe that with the variety of startups coming out that seed-level spray and pray, coupled with selective follow-on will likely get you in on big things.

Worst case, you have an existing relationship with a large number of startups, a percentage of which will undoubtedly go on to bigger things or exits -- the trick is of course in how big that percentage is.

This is evidenced somewhat by the increasingly large number of teams getting accepted by YC.