Sure but you have to assume that at some point in the future that Nvidia is going to start making those non-Nvidia GPUs very difficult/expensive to use in futur

Sure but you have to assume that at some point in the future that Nvidia is going to start making those non-Nvidia GPUs very difficult/expensive to use in future ARM designs. They could do this legally, technically through manipulating the reference designs to tightly integrate Nvidia GPUs, cutting support for third party GPU integrating SoCs or any of the above.