Duxfan, there are problems with your argument...
1) DTW is located on the southern end of town, but within an acceptable driving distance for the market. It is actually about equal distance from most parts of Detroit, as it is to Toledo, so that brings a lot of Toledoans up there to fly. However, say you live in Detroit...you have to drive quite a ways to get to Toledo, which is located on the far western border of town.
2) Detroit already has budget carriers...Spirit is a growing presence there, it offers nonstop service to several Florida cities. Also Southwest has a good presence there.
So, given the inconvenience, and the availablilty of various low fare flights out of DTW, I really doubt that there was any lure for the Detroiters to schlep down to TOL for any reason, except just to get to Atlanta.
Also, they are stating that the reason for the pullout was the lack of full fare pax. The planes had high load factors, but most of them were deep discounts. Understanding the above factors, what business traveler from Detroit in their right mind would go an extra hour or so to TOL (with traffic on I-75 being an extra "joy"), when DTW has tons of nonstops to Atlanta already on NW and DL?