I'm from Europe, and I like the Paul Graham Essay from 2006, http://www.paulgraham.com/siliconvalley.html , where he claims there are 3 necessary conditions to build a startup ecosystem in any city or region:

1. A large city or metropolitan area with high quality of life according to nerds and their preferences

2. excellent universities or career opportunities, so young gifted people are motivated to move there from 1000s of miles away

3. Capital availability (Venture capital, private equity, unspent cash looking for investment)

Most European Cities fail to provide all 3, and even then these conditions are not sufficient to build a successful hightech startup.