It's true though. The financial industry controls an incredible amount of wealth in New York. I think most people don't really appreciate the scale of it.
http://www.pionline.com/article/20100308/CHART2/100309910
J.P. Morgan asset management (i.e., nearly all the hedge funds J.P. Morgan owns) is only $53 billion.
If all hidden costs were taken into account, Wall Street would be less competitive which would leave more space for healthier financial products.
He does make a good point about talent though: Most of the good quants and algo guys are already employed, have years of vesting options, and can probably retire in 10 years if they stay at whatever fund they're working at. The base salaries are 6 figures, and with bonuses and employee stock plans they're probably pulling in closer to a quarter of a million annually, so your chances of recruiting them to a startup to live on top ramen for a few years are slim to none. Sorry, that's just the reality here. I'm sure you can find some fresh-faced college grads a lot easier though.
I don't think "Sorry, limit one industry per city" is a valid rule.