In my last full-on japanese company it was basically impossible to find any developer with more than 3 years experience by accidental design because:
1: No applicants studied computer science in university so they started learning when they joined the company and were assigned a development role.
2: After 3 years they they got promoted to a "manager" level role and stopped doing development. There was no concept of junior developer -> developer -> senior developer progression. If you wanted promotion you went from developer -> manager; it was the same for sysadmins. Their IT and development suffered heavily for it.
A team of 10 "western" style trained senior developers and sysadmins would have been able to do the work of 50 current employees at least for a large overall cost saving even with higher salaries.
Just the way things worked. Japan is indeed very different when it comes to how the workplace works in relation to tech in traditional companies.