Keep in mind that Apple is also exclusively building Macs with AMD graphics cards. They don't even support Nvidia cards as eGPU anymore. The rumour is that Nvidia is not willing to do any customised designs and someone at Apple is very upset with Nvidia.
https://www.extremetech.com/gaming/150892-nvidia-gave-amd-ps...
> "Nintendo Switch is powered by the performance of the custom Tegra processor."
Any reason to believe that will continue to be true when Apple move to their own ARM chips? No technical reason they couldn't keep using AMD GPUs, but Apple seems to be leaning pretty hard into getting as vertically integrated as possible.
I think that's a large component, but I'd like to add, ontop of maybe pricing and the like, Nvidia is being a dickhead in openness towards their hardware/software stack. Which, documentation of which is determined important for AAA game optimization over the course of operation of the console.
Additionally, there are important aspects of AMD's GPU architecture that are adventitious for teams squeezing the most amount of performance out of a fixed platform. Specifically, as far as I am aware, AMD's compute is much more flexible in context switching while the graphics pipeline is active, which at least used to be a problem for Nvidia's architecture.