[jack1243star]

> A system fails when its natives don't know how to use it.

They definitely do, it's just that hand writing has become a more niche use case in modern society (regardless of the language).

If you removed all kanji in a block of Japanese text (replaced with kana), I'd expect at least a 50% reduction in reading speed for natives, and some errors in comprehension. They're fundamental to the language.

[latentsea]

You wouldn't expect the same 50% reduction if the natives had been educated under that paradigm and suitable adjustments made to the system like adding spaces etc to accommodate it.