Is the FX revolution fizzling?

True - and that was when lenses weren't being pushed in terms of resolution.

To get much past the resolution of the D7000, or D800 centrally you need good, meaning expensive, lenses. It might actually be cheaper to make longer larger format lenses for the same 'reach'

If you're at the resolution of the lens, what is lost in using a larger sensor if the incremental cost of the larger sensor is small?