I dont follow this as much as others but if interested I have no problem being "checked"
Im almost certain that Intel could not make the chip that Apple wanted, they didnt have the capability to squeeze/shrink more transistors onto the chips, whether this is the key reason I dont know but I do know its been speculated for a long time now. I thought this only from the "investment" point of view as where I learned it, a Wall Street perspective at the time.
I briefly looked this up but have read about it some time ago, not necessarily from this publication and think it was an investment piece. Intel always behind, like 3 years behind even with their 10nm chips never mind the foreign manufacturers new 7nm chips.
"Stepping back and picking this announcement apart a bit, we had a good idea that Apple would be stepping away from Intel because, frankly, the company has
continuously dropped the ball in the last handful of years. Chipmakers like Qualcomm and Samsung are already delivering products based on a second generation of 7nm lithography while Intel struggled mightily just to get 10nm chips into products late last year. What this means is that, in a relatively short window, Macs with Intel chips have
gone from the best performance-per-watt to the worst."
Source =
https://www.inputmag.com/tech/apple-arm-chip-cpu-hardware-details
The reason I knew of issues is I was looking at it from a beat up company investment outlook. Buying a company beat into the ground from missteps. Glad I never touched this one.