That's kind of the crazy part though - how the hell does something you use and abuse every day, that you by definition leave out in the elements, not depreciate? Or at the very least, it is messed up that the depreciation is so minimal compared to the appreciation of the home (and not the land)

The land I can see. Land is in limited supply; AFAIK it's mostly just Hawai'i that's making more on occasion, and that's about it. But the actual building should depreciate.