I think the problem with that logic is that the people at the 'top of the heap' - VC's, CEO's and the like are not the ones being priced out, mostly. Granted, a company might open an office somewhere else, but that's after it's already large and established.
So you're kicking the marginal (in the economic sense) people out into marginal places where they have less access to what made the original area such a great place to have a job.
