I think those franchises would died with Nintendo. Of course the IPs would be sold, but I think they would lose their magic, the philosophy behing them. Just look at who are leading the teams at Nintendo, most of them work on the first nes and gameboy games. They have been with Nintendo for a long time now. The new ones that join the company have the philosophy pass on to them to make sure they maintain what make Nintendo special in the futur. Just look how carefully Miyamoto is passing Zelda to Aonuma even thought he is there for quite a long time too. That's also why Iwata once said he would rather develop their games internally than lending the IPs to other studios.
I doubt Microsoft would be able to let everything untouched. heck look at what happened with rare. I bet Nintendo would change just like rare did. When you see everybody saying that Nintendo should go mobile except Nintendo themselves, you can already know what would happen if they go Bankrupt. Quick cash in... Nintendo might be slow at producing their game and have softwares drought, but they are still the ones making the best games on average in the industry. Nintendo going bankrupt would hence be terrible, but it not even close to happen.