But even then they still use Hanja to disambiguate sometimes.
edit: obviously Kana has already been created
https://ja.m.wikipedia.org/wiki/%E3%83%AD%E3%83%BC%E3%83%9E%...
I'm personally fine with both romaji and kana (learning kana is not a big cognitive burden anyways).
I'm even fine with kanji (or Latin or anything) if people learn it voluntarily. What's not ok is kids being forced to learn them in school.
But even then they still use Hanja to disambiguate sometimes.