Seriously, I think over-supply of start-ups will crash prices. Yes, there is no limit to wealth creation, but even so, it is easy to upper-bound wealth creation over, say, the next 5 years. We can say with confidence there won't be more than, say, $10 billion worth of web start-up acquisitions over the next 5 years (in total, not per year) - that was about the total in the last 5 I would estimate and I think I am being fairly optimistic here. Even that $10 billion would be parceled out in the 80-20 rule - a couple of YouTube home runs, a few singles and doubles, and the remaining mass of start-ups have to fight over a fairly small pot of gold.
My objection is consistent with economic theory: over-supply leads to serious price crashes, even when you make the favorable assumption (which is not exactly true in the start-up case) that in the long run, the over-supply can be absorbed.