Apple is so ridiculously ahead in the ARM chip market... imagine if they'd sell to 3rd parties and the single thread performance on these laptops was 2x. Makes me wonder if they are about to make the same move on the lower speed MacBooks.
They already have a arm chipset working as controller in the latest iMac. I'm sure their end goal would be to get rid of intel as soon as they can. Using intel chipset gives them uncertainty. It leaves control out of their hand.