Looking at demographic shifts in Toronto, San Francisco and San Antonio, geographer Jim Russell argues that migratory patterns rather than taxes or density affect innovation in metropolitan areas.
According to the Canada Mortgage and Housing Corporation, fewer people from other countries moved to Ontario in the last year and more people moved out. Russell suspects they all fled to Alberta, "where the jobs are."
High rents in urban areas also contribute to out-migration.
Studies by Trulia, a real estate data analyst, show that California is experiencing in-migration from incomes larger than $200,000, while poor and middle-income cohorts drive out-migration to other states.
Where are low and middle income Californians going? Texas.
Ryan Avent's book The Gated City argues that high productivity places like urban cores also have a high cost of living. Density increases would make them more productive and lower the cost of living, optimizing their attractiveness.
However, places like San Antonio, which are expanding outward rather than up or in, are increasing their productivity through in-migration and low home prices, writes Russell who recognizes an almost irreversible trend in the demographic shift driven by home prices.