Since these are software specifications being leaked, I guess we can assume the NX is just a cloud service after all. There will be software clients for any hardware that is powerful enough to match these specs that wants it.
Nintendo will stay relevant because you can only get the premium experience on their dedicated NX clients.
That little box thing they patented will be the middleman that allows for cloud calculations as mentioned in the patent, but also provide an interface for plugging in Nintendo hardware like Wii/Wii u controllers and sensor bars.
It will play a huge amount of older games, and will be doing it via video streaming technology that worked on with the Wii u. Battery life will still be good because it's streaming video, and not doing any realtime rendering on the device itself.