Anecdotally I know some artists who have moved out that way for an abundance of cheap space - not empty office buildings as another poster pointed out, actual cheap art space.
There's a real potential for Detroit to develop major bohemian settlements now that every major urban center in the US is squeezing that demographic out rapidly (SF, Brooklyn, Seattle, Portland, etc). There can be a spectacular cultural resurgence for the city.
Speculators are probably hoping they can turn this into a Brooklyn-type situation. Get an influx of artists and creatives attracted by cheap, plentiful space, and then flip said property to wealthy professionals who are more bohemian in their own heads than in reality.
The problem is that Detroit doesn't really have that strong of a white collar job base. You can get the broke artists in, but there isn't really a ready pool of professionals to flip to. In that sense it might be ideal - it's possibly an ungentrifiable fortress for creatives.