To clarify, largely do not mean completely solved, right? It's not perfect, yet. Either way, I should have qualified by saying I think it's a largely solved problem as far as the technical implementation.
What an artist does with that implementation is always another matter, and it will always be down to the artist to create a pleasing final result. Specularity is one thing I think artists gets wrong all the time. At the artistic level, games often deliberately go for a more cartoony look, too.
And the uncanny valley thing is very subjective, no?
I think this is more than good enough for real-time games. Of course, you will probably say, "no that sucks, uncanny valley!"
One thing to notice here is that the albedo (diffuse) map (texture) used can be very crude/simple, as it is simply one small piece of the puzzle.
If you have looked at a video, or even screenshots, like the digital human ones, where the focus is solely on the subject, often close-up, that is very different to see it running in a game, where you are less likely to notice small faults.
These days, I think facial rigs and animation is the cause of uncanny valley, to a higher degree than skin shaders.
Can you post an example? All the fake skin I’ve seen is still marching into the uncanny valley (video at least)