What kind of software could Nintendo make for XB/PS that wouldn't cannibalize their sales? Or do you mean more like a deal to allow Sony or MS to use some Nintendo IPs in their games a la Smash?
Developing games for ios and android makes sense from a business perspective because of the ubiquity of smart devices. Everyone has at least one. Having Nintendo IPs appear on those platforms allows them to increase and maintain mindshare among the mainstream. It's a low cost, highly profitable move, and an absolute necessity if Nintendo wants to remain relevant. Same with movies and amusement parks. Bringing their games to xbox and ps is literally the opposite. It would be expensive, time consuming, and cause irreparable harm to their hardware business to have the best versions of their IP's on competing platforms.
