Bruce Sterling, quoting Victorian essayist William Dean Howells, explains the appeal of pictures of ruins:
The truth is, one cannot do much with beauty in perfect repair; the splendor that belongs to somebody else, unless it belongs also to everybody else, wounds one’s vulgar pride and inspires envious doubts of the owner’s rightful possession. But when the blight of ruin has fallen upon it, when dilapidation and disintegration have begun their work of atonement and exculpation, then our hearts melt in compassion of the waning magnificence and in a soft pity for the expropriated possessor, to whom we attribute every fine and endearing quality. It is this which makes us such friends of the past and such critics of the present, and enables us to enjoy the adversity of others without a pang of the jealousy which their prosperity excites.
Seems spot-on to me, and I say that as a committed addict of Urban Decay and the like.