Today we don’t see musicians complaining about that
Are you joking? Musicians are getting crushed under the weight of streaming services, which pay them a few cents unless they reach huge numbers of streams, and give customers a convenient "access-everything" platform which incentivizes NOT purchasing albums (even though they probably spend the same amount on subscription and in turn never own a single piece of music - Spotify shuts down, all your music is gone forever). Regular gigging musicians complain about streaming all the time.
Pirating MP3s is, and was, illegal. People got arrested for it. Musicians complained about it (ever heard of Metallica?). At the end of the day, it became something you just have to accept in a lot of cases because it's impossible to catch everyone, but it was never LEGAL. Also, there were some instances of people downloading music and then going out to buy the album for various reasons (didn't have the money at first, weren't sure if they would like it so tried it out before buying, wanted to support the artist, etc). Not everyone, obviously, but at least there was some recuperation of lost revenue. And there was always the legal barrier (depending on your location) and the general sense that you were in fact stealing. AND, to top it all off, the end product was still the work of a specific artist.
You can't compare that to genAI, which is like legalized stealing, but then recombining the stolen goods into something unrecognizable which now has no direct connection to the people whose work it was based on. Even streaming, which overall kinda sucks, is still putting your name and album art on the page at the very least, and throwing you your scraps. GenAI does no such thing.












