> Paying the lowest price you possibly can nearly always means someone along the way was exploited
No, I agree with that. But that's still engaging in charity, right? Voluntarily paying more for something that I could pay less for, so that artists will have a living wage, workers won't be exploited, etc etc.
Your "sustain something you want to see continue to exist" suggests something else, though. What it suggests is that I have a good practical reason, on the basis of wanting to see good music continue to be created, to personally pay more for music. I think this is incorrect.
If I was of the opinion that only a few artists made really great music, it might make sense to exclusively fund them so that they would continue doing so. But that's not the case: music is an extremely cheap commodity these days, because high quality production is so easy (can even be done with free or cheap software on an old laptop). There's enough good music put out there for free by people just doing it as a hobby to last a lifetime. You can't compete with that; a "fair share" of nothing is still nothing. Similar problem for Uber drivers: when there are too many drivers, the cost per ride gets driven through the floor. That's true regardless of whether Uber are exploiting their drivers (they probably are).
I was evasive in my original reply, so let me put my cards on the table. I do think that voluntarily paying more for something than it is worth (its fair market price) is charity. And I don't think it is practicable to fix the problems with artist remuneration by encouraging everyone to be charitable. And I think it's a bit ludicrous to try to commandeer the word "fair" to mean something other than the market price, if you're not going to reconsider the more fundamental assumptions behind having a market in the first place.
I would argue that if you want music to flourish, in something like its present democratized form, you need to do just that. Music should be understood as a human good - both creating and listening to it. All music is good, even bad music. All musicians should be supported, even those whose music wouldn't be popular enough to earn a living wage at the market price. Recall that even the Beatles were supposedly on the dole at one point.
On the other hand, we could decide that music is simply not all that valuable to us, that creating more music than anyone can reasonably consume does not promote any particular human good, and let the current proliferation of music die. That's also a valid outcome. What isn't valid, to my way of thinking, is valuing music and then thinking that charity ought to be our way of responding to that value.