> My point was that for a given language, the writing system tends to evolve to the point where each glyph contains just enough distinguishing features to not confuse it with any other glyph.

This is absolutely not true. If this happened, you would have a very bad writing system.

Human communication systems have tons of redundancy in. The actual regular alphabet used by English has tons more shapes and detail that you are accounting for, and it uses it incredibly inefficiently. You can create a huge number of additional letters using the shapes that the alphabet is using.

And this is a good thing. It adds redundancy, and it very specifically is not the case that "each glyp contains just enough distinguishing features to not confuse it with any other glyph" - in fact, it contains far more distinguishing features than you need! This is to allow you to recover the information when things are unclear. There is excess information encoded as a form of error correction.

This is true for writing systems, for language grammars, for vocabularies, for every part of human communication. We always over-specify, to allow for understanding even when the receiver misses out parts of the information.