The other approach would be to say that since the Cloud LLM providers ignore copyright when they generate models, that you cannot claim copyright on AI generated output. Which is basically the end of copyright, and maybe that's okay. Society evolves past many ideas.
Valid concerns about mass harvesting of open source code (and art,science,literature,etc) by proprietary Cloud LLM providers without any attribution, who generate proprietary work from it. I don't know the solution. Perhaps a tithe of their profits could go to original creators.