If they want to avoid paying for the creative effort of authors and other artists then they should also not charge for the use of their models.
How about the AI providers? they operate on thin margins, and make just cents a million tokens. If one provider is too expensive, users quickly switch.
Maybe the users? Users derive the lion share of benefits from AI. But those benefits are hard to quantize.
Maybe a blanket tax? That would simplify things, but would put all creatives on a quantitative rather than qualitative criteria.
I think generative AI is the worst copyright infringement tool ever devised. It's slow, expensive and imprecise. On the other hand copying is fast, free and perfect. I think nobody can, for science, regurgitate a full book with AI, it won't have fidelity to the original.
The real enemy of any artist is the long tail of works, sometimes spanning decades, that they have to compete against. So it's other authors. That is why we are in an attention economy, and have seen the internet enshittified.
The most creative part of internet ignores copyright royalties. From open source, to wikipedia, open scientific publication and even social networks, if everyone demanded royalties none of them would be possible.