I don't know about that.....even though El Castillo is covered in grass and the top is a little bit bent, it is fairly intact and close to the original shape, just very overgrown. And I'm sure that the inside would be almost fine too.
However, it is a massive pyramid (one of the strongest shapes/structures) so I suppose that a normal stone house could have collapsed completely.
El Castillo is a pyramid of almost completely solid stone. There is a vast difference between that and a one foot thick wall.
It would probably still be more recognizable than an Osgiliath war-bombed house though.
A stone house that had been abandoned for two thousand years would literally not be visible, as I think I demonstrated with my point about the forts along Hadrian's Wall.