Looks to me like they chose based on profitabity. First, they have the growing low-regulation cities of the south which have plenty of customers. Second, they

Looks to me like they chose based on profitabity. First, they have the growing low-regulation cities of the south which have plenty of customers. Second, they have the high-tech centers of Portland and San Jose which have so many tech customers that Google wants to serve them even though it is not low-regulation. Poorer regions, non-tech regions, and high-regulation regions are all less interesting. Detroit, for example, hits the trifecta of all three disadvantages.