Well, HUD wants to sell it to someone who intends to live in it, "owner occupied", and most of them are garbage. Some from the pictures are almost certainly condemned/require significant repair before it could be considered safe for occupancy. So you need someone willing to invest the time and money a flipper or real estate investor would, to live in a really cruddy house.

In short, the people who have the money to fix it want to live somewhere nicer.