This isn't surprising, Apple would have to be completely off their rocker to even consider putting an NVidia chip in a Mac.Mobile and desktop dies were always exactly the same. There is no difference between BRANDING of the GPU dies currently in Nvidia lineup, but GPUs are heavily down clocked compared to desktop ones. Thats why you get GTX 1060 currently. GTX 1050 is coming soon with under the 75W thermal envelope, on desktop, and around 40W in Mobile.
AMD offers already RX 470 in laptops, in the same branding manner as Nvidia. You can argue with Apple, but they will not use the Pascal GPUs. Look no further than kexts in macOS Sierra. There is support already for RX 460, 470 and 480. No sign of not only Pascal, but Maxwell GPUs in the system.
By the way Mac OS Sierra rocks big time. It looks like a release that most can transition to right away with little in the way of problems.