It all depends on so many factors in so many neighborhoods. Each individual property must be asessed for it's potential and needed repairs, then the neighborhood itself, then the potential renters. And this over several cities. All would depend on the quality of the managers hired. To attempt this on a large scale, especially when it has apparently been tried and failed in the past seems risky to say the least. How can one man oversee such an operation the more it grows? How much of your portfolio would you be tempted to invest in such a outfit?
Also of note in this very interesting article:
Redbrick's first fund, which started with $3 million of equity and has used borrowings to acquire about $10 million of properties,
After reading the article, I think he probably does have a business; he's not shooting for short-term profits turning the houses over but is treating this as a wide-scale rental business with appreciation as a benefit, not a major profit center. However, since he is using a lot of leverage to do this, I think it would prudent to still try to hedge at least some of the $10 million he has borrowed.