The AI topic is an interesting one in gaming, im a Web Developer and our company is reluctant to use AI because we handle a lot of sensitive client data and also value our intellectual property. Therefore we don't want to give AI code (for say helping write code) access to our code or the potential to see/use our clients data if we assimilated AI functionality into the application itself. We are under quite strict regulations to conform to this sort of safety/security measures but I can totally imagine Nintendo being reluctant to use 3rd party AI software with there products. Then again I have no idea what resources they have, but AI is still pretty specialised(although that term is very vague in what it means), I'm not convinced it's something they would want to take on themselves.