You are looking at this differently than the parent post. You are looking at cross-industry inside Japan. Parent is talking about inside Japan vs outside Japan within the same industry/job.

If you look at public data on somewhere like levels.fyi, there's a big gap in pay even within the same company, at the same level. I'm most familiar with Seattle comp, and same tier of SDE role is a 30+% paycut from Seattle to Tokyo at FAANG companies.

I also know someone who left a FAANG company here to go work in Japan for awhile. They had to move from SDE to Data Scientist + got a senior role at the new company, and even then they struggled to get anywhere close to their previous comp.