Buyer's market and acquisition is no guarantee of success
It's a buyers market and not a lot of buyers at that. Nobody is going to repeat the stupidity we saw with Data Domain and 3PAR acquisitions. With this many companies looking for a buyer and running out of cash, buyers can afford to wait for a good deal.
Even if one or two of these start-ups get acquired, it's no guarantee they'll last. NetApp is in pretty sorry state right now and needs to acquire something exciting. However, when it comes to acquisitions they're all thumbs. They've failed to make any acquisition pan out and the acquired talent jumps ship quickly due to the internal politics. They eventually mothball it because they can't figure out how to sell it.
I suspect some VCs will get their money back, but I'll be surprised if any of these companies see a huge payday.