Robot companies don't appropriate the work of other people. That's the fundamental point of contention here: that LLMs cannot be trained without the human labor of the authors; yet, they directly compete with them in the marketplace. I haven't yet seen an LLM trained only on public domain material, but its capabilities are likely to be very limited.

That's also the key political compromise underlying the notion of copyright: that someone is entitled to the fruits of their labor, and should not be economically hindered by a product that could not have existed without said work. That's the basis on which the "derivative work" copyright doctrine emerged: a work sufficiently original that it does not displace the work on which it is based. LLMs fail to abide by that political compromise by a country mile.