Earlier quoted context omitted.
Actually it's a perfectly succinct and easy notation. Not many musicians have a "hard time" getting it, except for those that never cared to study it. In fact, in the history of jazz piss poor black kids that never went to school managed to master music theory just fine. And an enormous amount of people all around the world. The particular example you mention (chord naming) has something like 1/100 the difficulty of…
Piss poor black kids that never went to school can still have good ears. It's all about the ears.
It is the conceptual framework & vocabulary you use to talk about music, not perform it.
If kids love performing and listening to music, they'll want to talk about it. And initially they'll be limited to things like "I love that thing it does near the middle when the bass is going baBONG baBONG baBONG then everything suddenly get really quiet and strange".
That's obviously ridiculously imprecise, right? And aren't you curious to know what "strange" means in this context? Suppose you want to write a piece of music that sounds "strange" like the piece you liked, but more so? So even piss-poor black kids end up with a thirst for a subject that looks pretty dry to the unmotivated.