Have relatives that live in Japan. A lot of what they are doing is to survive earthquakes. But even so........somebody was taught math and engineering.......and they are using. it. But skillset with tools is amazing.
Prior to about 1998, on the west coast, high quality, fine ring-count, old growth doug fir, hemlock, and yellow cedar logs brought a large premium price due to the Japanese demand for traditional framing like shown in the video. That demand changed almost overnight when they changed to more western construction practices.
Also, their use of a lot of heavy tile roofs led to a lot of colapsed buildings when the traditional methods where used. I have a hunch that economics plays a big part as well.
You cant hardly give away large diameter logs nowadays; the new automated mills can't handle them.