Think he weather would be a big hindrance and the fact that it's not really a tourist area. The latter is probably the bigger reason though honestly. Paris is about the same distance north as ours and gets cold weather and snow too. However historically it has been their lowest performing park so that's not exactly a good argument as weather could be part of the reason. But Orlando, Anaheim/LA, Paris, Shanghai, Hong Kong, and Tokyo are big business and tourist destinations that draw lots of people in every year. Michigan doesn't really have that kind fo draw to pull people there outside of the park.