WTC: The End Of Business Clustering?

How do we 'rebuild' hundreds of private decisions to cluster? "Urbanists wonder why certain activities cluster. Analysts insist on the importance of many things. But until a month ago, the best reason why any financial services firm would locate in Lower Manhattan was because hundreds of financial services firms were already there. Shockingly, of course, they no longer are. So now, instead of only new firms deciding where to locate when hundreds have already located in Wall Street, we now have hundreds of firms making that decision all at the same time. All these decisions must be made without the benefit of history, in the sense of an existing Wall Street."