“what would it take for musicians posting their own music to also point to music posted by other musicians?”

Merely a vogue for people doing it–if a few people started, and the people they list started, the same viral thing that helps videos of schoolchildren playing “while my guitar gently weeps” would help musicians spread each other’s word.

It’s as if we all have been living in a Second World country, and then moved to east Hollywood.
We’re all still a bit tempted to struggle with other customers over who gets the fresh fruit.
Yet, we need to realize that there is plenty of fruit to go around, and that if more customers request the usually-hard-to-find fruit, then it will start showing up on the shelves, virally increasing its popularity, leading to more exotic fruits gaining mass acceptance, and onward.