I did not talk specifically about Japanese, and I don't think the OP did either.
And I should clarify for that -- character mostly stop changing once printing press is introduced, and stop almost completely once digitization is completed. Of course common language get digitize long before, but all common language seems to have digitization completed 10-20 years ago.
You are thinking about alphabet-based languages where the creation of a new word does not involve the creation of a new character. We are frequently creating new words which require "workarounds" (sometimes just using a romanisation) until it's properly encoded.
Who are we here? The Japanese have a syllabary. Even the Chinese are, as far as I know, almost never creating new characters (when something new is called for, as far as I know, a soundalike old character is the most common solution).
There are languages in India with tens of millions of speakers whose digital representations are still poorly implemented, partially because the speakers of those languages rely on English instead of their own language when using computers.
And I should clarify for that -- character mostly stop changing once printing press is introduced, and stop almost completely once digitization is completed. Of course common language get digitize long before, but all common language seems to have digitization completed 10-20 years ago.