Firstly, I haven't downvoted any of the comments in this thread, including yours.
2) It would seem odd for me to refer to San Fran as 'the city' from outside of the city, since, for me, 'the city' likely refers to either DC or Baltimore, depending on which I'm nearer to at the time.
San Fran might identify the person as being from out of town, but generally, that's exactly the type of person you'd expect to be saying something like that. Doesn't make it outdated in my view. If, perhaps, it is not in trend, that doesn't make it unmodern.
As for the brand of Detroit, admittedly, there's a lot of bad press about it from the outside. I'd argue that efforts like GrowDetroit are exactly designed to combat.
Lastly, the point I was making about DC is that yeah, it's a crappy place on paper, but it has benefits. Detroit might also seem like a crappy place on paper, but might also have its own set of unique benefits and luxuries even. As you mentioned, the low rent is a great advantage for a startup. As I understand it, there are plenty of areas in Detroit that are safe to be in at night.
Again, I can't really speak for it, having not been there, I'm just suggesting that perhaps you shouldn't dismiss it out of hand so quickly. Of course, it's your life, and I'm being pushy by suggesting you do other than your natural intention.