As I understand it, Trump's position isn't that NATO should be disbanded, but that members who don't meet their financial commitments to it shouldn't be able to rely on its support.
I think we'll have to wait and see; Trump was elected to 'drain the swamp' here in the US and may not be too concerned with the rest of the world. In which case, 'the rest of the world' had better see to its own defense. And really, given that Russia is much reduced from the old Soviet Union, why can't Europe take care of itself?