I don’t know why you would say it’s impossible. 10k people do it a year, it’s a well documented process. The biggest hurdle is probably the language? Since most people can exist in Japan without a full grasp of the language in more ways than other countries

That's a bald-faced lie. Anyone can apply after 5 years and it's not that hard. I know people who are naturalized here.

I've lived in Japan since 2009. In my opinion, most foreign residents who want to stay here long-term are interested only in permanent residence, and not citizenship. Reason being they don't want to give up their existing non-Japanese citizenship (which is technically a requirement for citizenship in Japan).