I get what you are saying, but this part above isn't a "natural order of things". For example, homes in Japan are expensive (perhaps representing an even larger fraction of lifetime earnings than in the Statse) yet they depreciate like they are cars.
My home is about 30 years old and honestly the only way you'd know that is by recognizing certain features and techniques that pin it to that general time period of construction and code requirements. It's not like everything shows "30 years of wear" on it. (Of course all the surfaces have been replaced at least once over time, but by mass of the house that's not that much; maintenance is maintenance.) So it seems sensible to me that it hasn't depreciated all that much, in the way that, say, a computer from the same time period is basically worth whichever is greater of "nostalgia" and "scrap metal" value.
For what it's worth, the 30 year old house will show wear in places you can't see, like the plumbing or the electrical wiring or the roofing. My parents' place is about 30 years old now and there's a fairly constant stream of small repairs that have been necessary over the last few years.
By the way Yahoo Auctions is much more popular than eBay in Japan so you might check that out.