The loss of population does not guarantee a continued slide toward obsolescence. Conversely, an influx of educated creative types does not necessarily result in an economic boom. Everyone has the potential to be creative, but not everyone is cut out to start (and successfully run) a business. The entrepreneurial spirit is something that needs to be sparked, and then cultivated. On the list of things that can serve as that spark: watching an exodus from a place that you love. In the above-linked Burgh Diaspora post, Jim Russell shares a story about Doug Dwyer, a former First Data employee who chose to stay in Boulder when his employer moved to Atlanta. The decision to stay required Dwyer to "think like an immigrant," and he has since founded a company, Mocapay, that employs 20 people.
When it's possible for the upwardly mobile to leave, those who stay behind by choice are bound to be more invested in their cities. These passionate people are some of the greatest assets that a city can have, and the fact that there are fewer other people around inherently makes it more likely that these passionate residents will bump into each other, share ideas, and perhaps start something exciting--as long as shrinkage is managed through smart urban planning to maintain some level of density, and to preserve downtown areas as places of economic and intellectual exchange. Especially when large areas begin to empty out, it's important to think about how to encourage interaction.
In a recent promo video for the new book Living in the Endless City, Saskia Sassen was asked what makes a city successful. She answered that "It’s their incompleteness that gifts them their longevity. A city does not become obsolete." Population loss does not equal death: it's just part of the process of rebirth.