You don’t like the guy in the vid. OK, got that. They didn’t show the actual chip. OK, got that, too.
Now tell me why it is not possible.
No, you tell me why it is true in regards to Apple and Amazon, which is the core statement in the article. Where is your proof? (None, whatsoever.)
I'm not going to tell you it's not possible. I'm going to tell you it's stupid. Why go to the trouble of redesigning an already designed motherboard from scratch to adman easily found, unnecessary, easily discovered on Quality Control IC chip, when the same function can be buried inside an existing IC, or just written to firmware or other code that doesn't invoke until a specific signal s received. Any IC chip that has access to the bus can have additional circuitry added in its multilevel that could only be found by shaving down through the layers and scanning with an electron microscope and reverse engineering its purpose. It could be stuffed in a memory stick. . . and for all purposes, no one would be the wiser. Perhaps monitoring might notice unusual energy usage, unusual traffic, etc. . . but you'd need to be monitoring.
So, while possible, why do it?