Even if you come to the conclusion that these models should be allowed to "learn" from copyrighted material, the issue is that they can and will reproduce copyrighted material.
They might not recreate a picture of Mickey Mouse that exists already, but they will draw a picture of Mickey Mouse. Just like I could, except I'm aware that I can't monetize it in any way. Well, new Mickey Mouse.
I don't self-host my music streaming currently (lack of funds) but I'm planning to in the future. I live in a large city and borrow CDs from the library to rip at home. This might not work for more obscure stuff or if you don't have a good library in your area, but this way I don't need to make more space for CDs and I support the library doing it. If I want to support artists, I get merch and/or go to concerts.