Houses in general..

I was driving through Fulham on Sunday and forgot having lived over this way for so long actually how grotty things are in parts of Fulham and Chelsea. I think the stark contrast between the stunning houses and those left to rot is just easier to see. I don't understand how so many of the once grand houses have been left to rack and ruin. They are just beautiful in terms of their architecture but somewhere seem to have been forgotten over time and there are a number of what look like squats on some really posh roads.
How do houses fall into such disrepair. Why aren't they sold before they get to this state and why, when they come up for sale again (or seemingly they don't) aren't they bought and then restored.
It is not just a couple of houses either, and i can't believe that they are all being inhabited by mad old cat women (like the film Grey Gardens) so why has it got so bad.
Perhaps it irks me so much because I just think about what I could do with one of those houses in Fulham....