Not your main point but it touched on something frustrating to me. Personally I had a very hard time finding metal bands I liked until I started going to a lot

Not your main point but it touched on something frustrating to me. Personally I had a very hard time finding metal bands I liked until I started going to a lot of shows. Spotify etc obviously try pretty hard, and with diligent effort you can prod it to cough up a metal band you haven't heard before that doesn't suck, but it's much better at playing music you already know about and like than it is at showing you anything new, at least for my subgenres of choice.