Presumably, a “Stop Killing AI” movement, mirroring the Stop Killing Games movement, would require a provider that revokes access a previously available model to make it open weights at the time of death.

These are not analogous. If you paid for an offline model, and you were somehow revoked access because it was phoning home, that would be closer.

If you were paying for an ongoing subscription for a service, that would be something different.

On the surface, there appears a difference between buying a game and paying for llm processing time. You haven't bought the model, so it is unclear to me why the same argument ought to hold up.