8 bits isn't "current", if you want "current" you get 10 bit panels. If you want "better than bargain basement" you get 10 bit panels.
At least where I live one of the differences between the TVs that CostCo sells and the ones that others sell are 8 bit (CostCo) vs 10 bit (others) panels.
I understand about the panels, but what about the source material? Is color information on a blu-ray stored at 8 bits per channel or is it higher? If the source material is 8 bits per color channel, I still think you'll see banding on smooth gradients no matter how good the panel is. I should try some tests...
Note that the panels are very unlikely to be true 10-bit; they're almost certainly 8-bit with temporal dithering. And the cheap panels are 6-bit with temporal dithering to 8-bit.
That is a good question. And strangely not as straight forward as I might like. "RGB" is 8 bit but video is not encoded with RGB, it is encoded YbCbCr [1], and the conversion from Chroma space to RGB space is fractional and depends on the Kr and Kb constants.
The math supports converting a YbCbCr 'pixel' into a 30 bit RGB pixel if your conversion constants allow for it. What is unclear is when quantization noise from the compression of the chroma signal shows up as bit instability in the resulting conversion cycle.
For TV I have no idea, but for a computer, you can get 10 bit per channel output from most graphics cards these days. You still have the problem of the source material being 8bit per channel though.
At least where I live one of the differences between the TVs that CostCo sells and the ones that others sell are 8 bit (CostCo) vs 10 bit (others) panels.