FYI: I was not commenting on the desirability issue which speaks for itself.

Explanation:

Say Detroit and people think one thing and one thing only regaring industry: AUTO INDUSTRY

Say San Diego and people think many things including: Defense, Biotech, Telecom, Tourism, Sporting Goods/SoCal Lifestyle products and eventually Real Estate.

Detroit lives and dies with the US Auto industry. SD does not live and die over any single industry.