Social melting pots foster technological innovation

This isn't true. Take any field of innovation, and you will find most of the best ideas coming from mid-sized cities and the suburbs. Technology, for example, is pretty well all coming from suburbia and mid-sized cities. If you take New York or London, their best days of innovation are well back in the past. The best music and technology and science is coming out of other places. The only 'innovation' coming out of London and New York, sadly, is the corrupt 'innovation' we see blowing up in the financial markets.