If foreign nationals are able to extract a lot of capital through rents then that's a sign that the government has made it too difficult to develop new rental housing.
This really isn't the case in Japan. It's extremely easy to develop new rental housing, and rents are fairly low.
However, it can be difficult for foreigners without a Japanese support network (like a blue-chip employer) to rent property in Japan at market price, because of discrimination by landlords. This isn't because of government policy, it's because building managers have the impression, mistaken or otherwise, that foreign tenants won't respect the rules, will be difficult to communicate with, or might skip town with unpaid rent.
However, it can be difficult for foreigners without a Japanese support network (like a blue-chip employer) to rent property in Japan at market price, because of discrimination by landlords. This isn't because of government policy, it's because building managers have the impression, mistaken or otherwise, that foreign tenants won't respect the rules, will be difficult to communicate with, or might skip town with unpaid rent.