They are technically already building GPUs, but specific to their own iOS and Mac hardware. Google, Microsoft and Amazon are actually doing something similar,

They are technically already building GPUs, but specific to their own iOS and Mac hardware. Google, Microsoft and Amazon are actually doing something similar, the GPUs and special-purpose chips and hardware they are building are built to run mostly on their clouds. They are not selling their chips directly to customers and I doubt they will. I suspect it will cost Apple and other companies a LOT to build general-purpose GPUs that they can sell directly to consumers, enterprises or data centers. Actually you can take a look at Nvidia's biggest current competitors - AMD and Intel. They have barely moved Nvidia's GPU market share in the past few years, and are unlikely to be able to meaningfully compete even for the next few years. It's not just about building better hardware, it's also about the ecosystem (CUDA etc) built on top of the hardware, which gives Nvidia a moat today and likely will at least for a few more years to come.