There is not enough profit in that compared to the risk. They're also not exactly aggressive about it (there are groups which host mirrors who charge far more/finance it in the usual criminal way of getting people to install malware).

To me, there's a "motivation gap" between what they get out of this and the effort it takes, so there's some kind of "ideology". Whether it's 100% what they say it is, is another question.

For authors (books) ~70% of all the book sales go to the publisher, not the author (trad pub): https://reedsy.com/blog/how-much-do-authors-make/

For musicians: depending on how big a name you are and which publisher you chose, the publishers compensation ranges from 15% (small name/indy) to 60% (big name/Universal, Sony) https://www.careersinmusic.com/music-publishing/

This is an industry with profit maximising as its goal like every other industry. If artists are broke, first take a look at the publishers.