The premise, of course, is that Mark somehow "got away" from Boston and was always destined to be more "successful" [your definition here] than any other founder. So there are really two main points: that this proves Boston needs to catch up with the Valley, and that there's another Mark lurking out there somewhere that must have been missed.
Let's start with the first part. Boston has needed to catch up with the Valley since the decline of Digital Equipment Corporation, if not before. That was, if I've got my facts straight, in 1992. So it's been nineteen years that Boston's tech scene has been dying. When I was at Harvard trying to get undergraduates excited about technology entrepreneurship in 2003, the club ended up electing me President because only eight people showed up and half of them were my friends. Apparently things have gotten better since then, but I'm still on the Harvard entrepreneurs mailing list and there's not much going on.
As for Mark, I've said plenty in the past. The key points are A) that people like Mark don't innovate; they copy; and B) if as much money was poured into another company as has been poured into Facebook, then we'd all be talking about that company and founder instead. (Twitter, anyone?)
If VCs are just looking to fund copycats, that explains an awful lot, but they should just admit it and stop pretending that they exist to support entrepreneurs. In the meantime, their returns will continue to decline as they ignore people who actually do come up with novel approaches to problem solving in favor of the coy and disingenuous who can convince millions to waste their time in a uniform manner.
There are a lot of bad ideas in Silicon Valley and a lot of bad ideas in Boston. But there are definitely some good ones, too. If VCs can't distinguish between them, they should either just fund everything in the hope that they'll just get lucky, or step aside and get out of the way.