> One interesting thing I learned while researching this comment was that a big reason Hanja disappeared was because Koreans gained literacy during the typewriting era, but before computer auto-suggested keyboards, and it was just substantially easier to make and use a letter-based typewriter.

If you look in the right places, you can find people complaining about how it's impossible to dynamically render hangul blocks, which means that a Korean font needs to define glyphs for every possible Korean syllable as opposed to just defining the elements of the system and letting a word processor assemble them as appropriate.

If that's true, I don't see how hangul could have had any typewriter-based advantage over hanja. From the typewriter's perspective, there's no difference.

The Chinese used typewriters by defining a typewriter code. Assuming that that was necessary for hanja, and also for hangul, why would it promote the disappearance of hanja?

If a typewriter code wasn't necessary for hangul, how did we forget how to lay out the blocks in between then and now? Hangul have been in continuous use for all that period.