I concur with your observations about the state of UHD today and confusion it is creating.
Some sets say they have hdmi 2.0 capability (including Sony), but nobody knows if its the full feature list of hdmi 2.0 to support all the standards of UHD. They may be able to support 2160p at 60hz, but there is no mention at all about color bit-depth and the color gamut to be used. Hopefully these TVs and projectors with such future proof hdmi port are indeed fully compatible with the specification and not part of it.
I do like that the spec also keeps support for 1080p. I would love to see UHD1080 next to UHD2160 were TV could also benefit from the higher color gamut and bit depth and color subsampling. We are far more sensitive to color and contrast than pixel resolution.