10 years ago I moved into the block that was built on the corner where the old Mercers Arms was, by the time I moved out 5 years later there were prostitutes using the bin stores for whatever they were doing and needles in the car park, horrible place
I remember the last game against Derby - Before the game I had a brief chat with some old dear who was stood on her doorstep (King Richard Street) taking in the carnival like atmosphere. She told me she'd been there since the mid 50's and I asked her if she'd miss the ground once it was gone. In an almost foreboding manner she replied, "Oh yes".
A fair few are unoccupied I think, so it's probably by-to-let investors not wanting to realise too much of a loss by accepting less, or not wanting to pay off their mortgage while having sold the thing!