Apple is already one of the largest
(if not the largest) customers of TSMC and they have plenty of experience designing some of the best chips on the most modern nodes.
Their ability to design a chip and networking fabric which is fast/efficient at training a narrow set of model architecture is not far fetched by any means.
It's worth noting that one of Apple's largest competitor at TSMC is, in fact, Nvidia. And when you line the benchmarks up, Nvidia is one of the few companies that consistently beats Apple on performance-per-watt even when they aren't on the same TSMC node: https://browser.geekbench.com/opencl-benchmarks
i'm seeing people all over this thread saying stuff like that, it reads like fantasyland to me. Apple doesn't have the talent or the chips or suppliers or really any of the capabilities to do this, where are people getting it from?