The Japanese need the time to get busy. Their work culture that demands that all the employees stay until the ‘boss’ leaves... only to be required to then go to a bar and get ‘s41t-faced’ in the name of workcenter ‘bonding’. That really leaves very little time for the average Japanese salaryman to actual get busy.
Or for that matter, look for a nice lady to settle down and get busy with.
Or to help raise any children, too.