There would have to be more to it. If cuda is just the software that Nvidia customers use, or nvidia hardware is chosen because cuda is better software, it's no

There would have to be more to it. If cuda is just the software that Nvidia customers use, or nvidia hardware is chosen because cuda is better software, it's not going to pass a market welfare test nor would monopolistic practices be found. Expensive switching costs per se aren't considered damage to welfare.