The climate and the geology here is hard on buildings, with typhoons, hot, humid weather, floods, landslides, earthquakes and so on. The climate and resources also dictate light wooden buildings rather than stone; the islands are volcanic, so there's a relative lack of hard stone good for building, and stone buildings are susceptible to earthquake damage.
And as buildings just weren't expected to last all that long anyway, there was little point in wasting effort and material to overdesign them. Make it last for a generation or two instead, and let people rebuild from time to time. Even temples and shrines sometimes schedule a periodic tear-down and rebuild of their halls.
A peculiarity of the throw-away mentality is that many houses have serious brick or tile facades only toward the street. Out the back they're completely plain, even unfinished-looking.
Today we can make buildings that last longer, but the idea that old houses - single-family homes especially - are near worthless lives on. The land is everything and the building on it is generally worth nothing at all unless near-new. In fact, old buildings may actually detract from the land price since the new owner will have to pay to tear it down.
And since you won't get your money back if you build to last, people usually don't. So you get family homes and apartments with badly insulated paper-thin walls and single-pane windows, no central heating, creaky floors, dingy fake wood paneling and cheap-looking facades. Buildings that naturally are nearly worthless after thirty years, further reinforcing the idea that old buildings are no good.
If a few far-sighted people started building for the long term, attitudes could change of course. But they'd be just one unfortunate landslide or earthquake away from looking less like visionaries and more like wasteful dunces.