BTW it’s already established that training AI models on copyrighted materials is legal without approval of the copyright holder, and IMO it’s unikely WP’s material would be an exception.

That isn’t accurate - this is a highly unsettled question, and there are multiple cases in litigation today.

WMF would need some better argument if they’d want to sue successfully, especially aginst companies that are sitting on 100x more money than them.

A better argument than what - that they are openly violating the licenses under which the encyclopedia is distributed? What more do they need?

They are sitting on $296M. Why aren’t they suing the AI companies to defend the contributors?

It transforms the contribution to no longer be “share alike”.