The first day I got there, chock full of excitement to see the city and get a feel for the place (really, people were laughing at my extreme enthusiasm about going to visit Detroit), I biked downtown for the jazz festival and was nearly mugged, or worse, on the way back around midnight (a bunch of guys in a van kept trying to get me to stop and approach the van, to help them get gas...there were gas stations within three blocks in either direction, and the guys in the van were young and looked perfectly capable of walking a couple of blocks to get gas...and the van seemed to be running fine and the guys were giving off seriously nefarious vibes, whispering to each other, etc.). I've biked through the tenderloin in SF in the middle of the night, walked through Brooklyn and the Bronx at 1 AM, and spent time in numerous so-called sketchy places; I travel full-time, so I've been to some interesting places, and I don't travel like a tourist. I try to see the real side of the places I go. I've rarely felt threatened in the nearly two years I've been travelling. I felt threatened in Detroit, on more than one occasion.
Detroit has a reputation for being a scary place because it is a scary place. And, while I enjoyed some aspect of my visit, like finding a walk-up outdoor movie theater setup among old abandoned buildings, and seeing little farms in urban areas (though they seemed to be in a somewhat bedraggled state; they seemed more like a media ploy that has played out rather than an actual sustainable community effort in some of the cases I saw), and the music scene is good, it doesn't make up for the sadness of the place itself.
Also note that those $6000 houses (and even less) will have property tax of several thousand per year. Detroit is still valuing houses at the rates of 10+ years ago, and the tax rate has climbed drastically in the past several years to try to keep revenue up to the level required to keep schools running, roads in decent condition, and police on the streets. Despite all the increases, the city is still experiencing significant budgetary problems. I looked into buying a house there, as it's cheap enough to be damned near an impulse purchase, but the cost of buying, restoring, securing (because you're going to need bars and cameras if you have a decent house within the city of Detroit), and paying the taxes on it will make it much more costly. Still incredibly cheap, but nowhere near $6000. And, you'll be living in Detroit. Not worth it.
Oh, and starting a tech company there? Madness. Notice that only one of those companies is actually worth more than a few hundred thousand (and it's not a startup, anymore, and hasn't been in a couple of decades), or maybe a couple of million, at best. That's not a coincidence. Those would be also-rans in the valley. I've noticed the same thing about most "look at us, we can be a startup hub, too!" articles. They mention a half dozen websites no one has ever heard of, as proof positive that the city can compete with actual startup hubs for tech companies.
It's cool that Detroit is improving. I'm sure some people will make solid money on real estate in the coming years in Detroit. And, I'm sure with an investor making a number of investments in Detroit-based companies, they'll eventually churn out a few decent-sized businesses, and they may improve the city further. But, it's not where you go if you want to start a tech company and you want it to succeed.