No mayor ever got reelected by making it easy for his citizens to move to Atlanta, of course, even when that might be a pretty good outcome for the movers themselves. But just because local politicians will eagerly seek federal place-based spending doesn't mean that the feds should comply. A sensible federal approach for upstate New York would invest in people-based policies that improve the economic futures of the children growing up there. Education is the best tool we have to fight poverty. If the children of upstate cities were better educated, then they would earn more as adults—whether they stayed in their hometowns or moved to Las Vegas. And people-based policies may actually motivate states and cities to spend more wisely, in order to retain their newly educated and mobile residents.
Glaeser earns his policy conclusion by considering what Minneapolis and Boston, both cities are Buffalo-like losers in the climate lottery, have done right. Education seems to be the key variable for explaining the economic and demographic differences between Rust Belt cities that share similar liabilities. In this regard, I think we can be somewhat bullish about Pittsburgh's future.
While Glaeser does mention some possibility of retaining residents, do not misinterpret that statement as another Border Guard Bob policy. Glaeser is embracing population decline as inevitable and even desirable. His approach is to make sure that the people who do stay, for whatever reason, are better educated.
I should add that Glaeser, like Ralph Reiland, does recommend tax reform as part of the turnaround equation. But if Buffalo starts attracting businesses, the region will also need to provide enough talent to run those new enterprises. Pittsburgh is already at least one step ahead of Buffalo, with plenty of human capital to spare. What is left to do is to create enough jobs to use up more of that excess capacity.
Otherwise, CMU graduates will start moving to Buffalo.