I think part of the reason that coffee shops are so popular here is simply because we otherwise lack quality public spaces. There's nothing to do here for the most part besides work, shop, eat/drink, and go home. We have few quality parks in our neighborhoods, hardly any walkable areas, and most libraries are underfunded. Coffee shops are one of the few FUN places to hang out, where you can read, listen to music, or talk in a relaxed, public environment. The historic, monumental, and urban qualities of Detroit add to the ambience, hence why the coffee scene has shifted in that direction.