Yes, the whole system is just basically component rendering (react) + a message bus oriented architecture (flux). The architecture is not novel, but I think the big change between React Native (or whatever they're going to call it) and any actual native application is the same difference between approaches like Cordova (formerly known as PhoneGap) and node-webkit. Platform independence.
The problem with "old school windows message loop" is the "windows" part (not because I don't like windows, "mac" or "linux" or "freebsd" or "solaris" could all go in there). Why haven't we abstracted presentation (functionality is a harder/more nuanced proposition).