"You've gone from "if you can hear it you can notate it" to "you can come up with custom notation and teach your custom markings to others and then they can read it". The two aren't even close to being the same."

To me it is very much the same - but perhaps the reason for that is that I am a Jazz Guitarist - a field of expertise where such notationary evolution has already produced plenty of alredy mainstream marks and abbreviations etc.

The assumpton may I think be yours, that if you read or write notation, then you are trapped by classical terms and symbols.

In fact, even in classical music, composers have often evolved written notation to suit their ideas, just as language and the written word have evolved.