Usually the land they are on is appreciating. The houses themselves depreciate. Sometimes the distinction doesn't matter - but here one of the things we are t

Usually the land they are on is appreciating. The houses themselves depreciate. Sometimes the distinction doesn't matter - but here one of the things we are talking about people knocking down serviceable houses to build new ones. This approach can sometimes even be compelling if land prices rise to a degree completely out of character with the homes originally built on them. See, for example, SF bay and Vancouver.