I’m not sure where you got that idea. Both permanent residency and naturalization are options. The only problem with naturalization is that Japan doesn’t allow dual citizenship, so you need to give up your other citizenship(s) to naturalize.

Been in Japan since 2015. Two more years and I qualify for permanent residency. Partner and I plan to buy a house once we both get PR (lower loan interest rates). Partner is from another part of Asia, and we both speak Japanese, so we enjoy life here.