[kkfdkerpoe]

I don't know about Japan, but sometimes older buildings may be genuinely better built than newer ones, which is a rational reason to value them in additional to historical value. The "expected service life" of a building greatly depends on how it was built and maintained. In my country even plenty of wooden houses from 1800s are still around, while modern ones from the 70's are often demolished due to mold problems caused by bad architecture of the time. 2000's apartments tend to to be pretty bad as well because of greed, they lack space and have impractical floor plans & general lack of quality.

[bobthepanda]

Japan had a forcing function until relatively recently; the last revisions to earthquake code were in 1981, and post-1981 buildings survive earthquakes at far greater rates than pre-1981 earthquakes, and are priced accordingly.

[throwaway6734]

To add to this, old growth wood that was used on older housing is of significantly higher quality than modern wood