I think the reasons have an underlying root cause and that is that the city grew too fast on the back of a single industry, so that it didn't develop the social infrastructure that sustains other cities. It's like they shoved 2,000,000 people in over 20 years [[1910-1930), let the sit for 20 years [[1930-1950) and then tok them all out in 20 years [[1950-1970). There was not time to gell. I think the whole thing is like a company that grows too fast with one customer and then loses the customer.