|Pyro as Bill said:
MS and Nintendo don't need to co-produce a console to achieve both of their aims.
MS would much rather give a slice to Nintendo than Sony/Apple/Google.
All MS/Nintendo have to do now is license Switch to dock to the Nextbox.
This is a good point. I keep wondering how this helps their console, but really they are looking to help the PC platform. All of this cross platform stuff makes the PC more attractive as a universal platform compared to a mobile device. It will be interesting to see if they start doing cross play on games that don't translate to mobile very well.