I don't know, a lot of your points make very little sense to me-but I've certainly been wrong before. Look at the following:
1. The numbers from 2007 (according to the FAA's site) have more takeoff/landing ops than JFK at DTW. You state that this is during a 'thriving economy' in MI. Michigan's economy has been about dead last in the nation for a number of years now. Local economy does not feed DTW.
Not so sure about your numbers, when I do a check of the world busiest airports. JFK handles 25% more traffic then DTW. As far as the econmy, the nations current unemployment rate is 6.1% is 8.7%. In 2004 the US was @ 5.4% and Michigan's was 6.8. So yes, Michigans economy is bad but it still continues to get worse.
http://en.wikipedia.org/wiki/World's_busiest_airports_by_passenger_traffic
2. ATL has no room to grow...at all. Add as many runways as they like, they still have massive gate problems and absurd delays. DTW still has more room to grow and, unlike ATL, has been built with future expansion in mind.
ATL has plenty of room for Asian expansion. How many flights a day are we talking? 15-20, at most, Delta can find room for 15-20 flight out of how many daily departures?
Most of the US to Asian departures leave around Noon east coast time, not anywhere near the peak hours of operation for ATL.
3. It has become basically an asian hub over time and has handled it with no problems, why on earth would anyone change what is arguably one of the most successful airport expansions in history? Especially to a complete disaster of a situation in ATL?
Just look at the history. How many European destinations did ATL/DAL have prior to the purchase of Pan Am? They didn't buy NWA for DTW.
I don't get it, if anything I would think DAL would be foaming at the mouth to get more of their aircraft into DTW rather than out, location and local economy mean little to nothing for the location of a hub.
Local economy means a lot to the location of a hub. Why is DTW such a hub for Asia? Answer, the auto industry. In 2001 GM had a market cap of close to 52 Billion, today it's 3.2 Billion.
I mean, who cares where HQ is located in today's technological and intstant communication environment?
O&D traffic still counts for something.
This is all my opinion, I could be wrong.