Talent retention is not a key driver of economic vitality. If it were, Chicago and New York City would be in a world of trouble. But that doesn't stop many from resorting to the tired brain drain refrain.
Top-tier research universities matter more than a vibrant urban core as focus shifts from talent attraction (too much competition) to talent production.
Most people don't move to Portland for the usual reason—employment. The City of Roses attracts talent with a focus on urban amenities and regional planning. But that strategy is easy to replicate elsewhere.
A captive labor pool (like working mothers who are unlikely to move their children) drives down wages. And as labor becomes more captive over time, the divide between rich and poor grows wider.
Return migration—native sons and daughters coming home after cutting their teeth in a Big City—is responsible for a burgeoning world-class restaurant culture in previously forgotten or ignored locations.