I find it super interesting that Apple is x-raying the PCBs for their compute nodes. Guess they took Supermicro inserting malicious devices into their servers very seriously.
At the time, at least, Bloomberg "journalists" were paid to move the market: https://www.businessinsider.com/bloomberg-reporters-compensa...
It is technically possible. There is adequate motivation by capable parties to do so.
Apple would be negligent if they did not make a serious effort to validate the hardware.