Geforce cards and 30 bits color (10 per channel) on windows = intentional restriction?

I am getting interested in having a profesionnal photo monitor, but realized that many of them work in 10 bits per channel color (which is supported on quadros).

But here is the curious line i read on nvidias website’s drivers from 2012:
“Implemented color depth 30 (10 bits per component) support for GeForce 8 series and higher GPUs”

So basically, it means that it is possible to enable this on these old geforce cards and not on the new ones?
Does it mean that nvidia can’t enable it for its drivers on windows while every cards can in fact handle it hardware-wise?

I hope someone will know the answer to this!