Currently live and work in Japan. I think a lot of it comes down to the fact that Japanese companies take a long time to change or make anything happen, and even though something might make sense, it isn't always right to rock the boat and do something new.
In this case, having to deal directly with with consumers vs big companies and selling parts in a new way probably isn't worth the time and risk for which ever salaryman is in charge of that department.
I'm not jaded I swear...