One thing I've noticed with it, that is a problem IMO, is that those in control of metal are sometimes slow to adapt to new ways of doing things. For example, it took forever for Spotify to get a good, diverse metal collection. Some of it was them not trying until the users started clamoring for it and some of it was labels like MetalBlade refusing to use the service. I'm not sure how much of that was tied to royalties but, I do remember a comment about how it would affect record sales coming from their head dude though.
Another example, Phil Anselmo was on Sirius talking about his side project a couple months back and was saying something along the lines of, "go out buy our record, don't fucking steal it by pirating it or some shit." Everyone I was with at the time kind of laughed at how out of touch he was with what is going on. No one steals music anymore (not literally, you can still find torrents but, piracy is down). You don't have to. You can get it on streaming services. You can listen to it on YouTube. You can find it on a number of places.
tl:dr - As the business model changes, they are slow to adapt and it affects the popularity, and bottom lines, of the genre in a negative manner.