Unless they’re under the yoke of Sony, Universal or Warner..

Just kidding, those three companies have been granted a state guaranteed monopoly over enough of human culture to be able to bully other entities like YouTube, Spotify or whatever, into accepting onerous terms.. (think youtube automatically (and legally) stealing ad money and giving it to these companies, for a video of a person playing historical scores on a recorder. Or Spotify accepting that the money you pay them will get rerouted to famous artists you have never listened to)

Musicians often don't know what they're signing up for, and sometimes labels change their mind about how to manage their catalogues anyway. There are a lot of great labels that do all the right things for artists and DJs, but it's a big industry with lots of players.

> Presumably musicians that want this release their work under a license that allows it.

Vast majority of musicians have no clue about licensing or copyrights or/and do not care, be it permissive public ones or strict ones.

If the artists don't know or don't care, then neither should end users.

Most musicians are effectively end users. A relatively small fraction of musicians are actually involved in the production and sale of commercial recorded music.

I think that’s too broad a definition and renders the term near useless (someone who can play an instrument regardless of skill).

In this case I’d regard musician as someone who derives significant portion of their income from making or playing music or at least puts in a significant time into becoming the above (practice, learning and playing).