This article summarizes it nicely: Most people don't care about musician's income from streaming services, or elsewhere.
There are a few simple reasons. One is the perception that musicians fall into one of 2 categories:
1. You are a rock star, flying around in a solid-gold Lear jet, making millions, living large, for "not doing that much", working a few hours a day. As Dire Straits said, "That ain't workin', that's the way ya do it. Money for nothin' and your chicks for free."
In this case, you're doing so well already that it shouldn't matter if a few people steal your music, because you're already rich.
2. You suck. Either your act just isn't good enough, or you haven't put in whatever "hard work" is required to build a fan base and "make it". And it's probably the former.
In this scenario, not only do you not "deserve" any money, but your music probably isn't even worth stealing, and you should be thrilled if anyone even listens to it.
In general, regardless of what you do, if you start a conversation with anyone saying "man, my job is so hard and I am so underpaid", you are unlikely to get a response of "you are so right, I agree, your life is so much harder than mine, it is so unfair".
You are far more likely to get a "welcome to the world, son", or a diatribe about how you actually have it far easier than me/teachers/someone else. When was the last time someone told you their job was easy and/or they were paid too much?
It gets worse.
Reading the article, you'll see that only 60% of consumers said they felt music was worth paying for. At all. That should make everyone in the music business extremely worried.
Some of this is the music businesses' own fault: they've spent years allowing many free music services on the internet and elsewhere to provide more than enough free music to satisfy fans. Major artists have given away singles and albums.
Years of mixed messages about the legality of downloads and streaming, companies being "illegal" and then legal, and blogs and websites offering authorized and unauthorized downloads have confused customers while simultaneously setting the expectation that if you want free music, it's out there, and probably legal.