Kids love simple motivations like save the princess as the driver to hook the player with an objective and let them proceed with enjoying the game. More complex naratives is not really the reason people play a Mario game.
Yeah, it is perfect for kids. Play Castle Crashers and you could have an idea of to which direction Mario could be taken without polluting the gameplay with cutscenes and narratives.
Nintendo is selling their IPs to Microsoft and this is true because: