At minimum they have to incorporate new data every month or the models will fail to know how many Shrek movies there are and become increasingly wrong in a world that isn't static.

That sort of thing isn't necessary for all use cases. But if you're relying on the system to encode wikipedia or the zeitgeist then sure.

They could, but that’s a recipe for going out of business in the current environment.

Yes, but at the same time it's unlikely for existing models to disappear. You won't get the next model, but there is no choice but to keep inference running to pay off creditors.