It would be very interesting to see a consumer-oriented ARM SoC from one of the other main manufacturers. I doubt that will happen, however. Their entire business is based on being a component in a chain of components, not being the entire thing. Although, for example, Intel makes some motherboards, some GPUs, etc...their business isn't based on putting it all together in one fabric for their end-clients. They'd have to control/influence more of the OS for that. Apple has it all: full hardware control, full software control, and it's all designed for the mass market consumer.