I disagree that it's fundamentally too early, if it's going to be another year or two of development. PS4 launched late 2013, we'll be coming up on its fifth year by the end of this year, so within the next two years would be a good time. Hopefully it waits for that 7nm shrink, but it's time to get developing. 7th gen dragged on terribly.
They already used a die shrink on the GPU in the Pro so it won't be as big a generational gap over that, but the CPU could improve drastically. If something could be worked out to use something like this it would be amazing, but not likely with Intel margins.
https://www.anandtech.com/show/12572/the-intel-hades-canyon-nuc8i7hvk-review-kaby-lakeg-benchmarked
I'm just curious how well they can pitch it to non VR and non even 4K people, a lot of people have perfectly great 1080p sets. I do believe there's a lot of room for graphical growth even on 1080p though and we jumped too early to trying to squeeze 4K out of consoles.