There are multiple books and papers written about what happened in Japan in 1989. It's no surprise that a small market like "lugged bicycle frames" started to go away during that period, especially with newer technologies and cheaper building processes starting to emerge. Japan was never a huge player in that field in the first place as they did not have the heritage, master frame-makers nor make anything superior to their competition (like they were doing with cars and motorcycles throughout the 70's and 80's).
Yup. So do you know when Japanese and then Taiwanese lugged frames disappeared entirely from the US market?