The story is lead abatement law in MD making these houses worthless and ultimately abandoned. I thought about buying several houses in Baltimore about 12-13 years ago. They were very cheap for the return on rent. Fortunately the wife wasn’t into it. I later found it was very expensive to get a lead abatement certificate for a legal rental unit.
The other thing is the stupid ground rent law. In many of the neighborhoods, you buy a house but only rent the ground under it, and it has a separate tax bill.