sadly if you try to be a good landlord and make a slim margin, you'll get dumped a huge repair bill/tax increase/other expense and now you're running the appartment at a loss. At that point you either sell it to a company willing to exploit it or you have to be less nice to your tenants and ignore repairs or charge more. Most people choose the first which is why we end up with terrible landlords.

aside: heard someone in that exact situation running low income housing, on a phone call with an expert talking to the government. The expert said "any prudent management would raise the rents the maximum allowed amount"