[MBCook]

Apple hates being beholden to one company. It’s bitten them many times in the past.

I suspect if anyone else could keep up with TSMC Apple would still dual source.

But between their lead and the benefits of being such a big customer they get first crack at the cutting edge stuff, single sourcing manufacturing probably makes the most sense.

And their interests are aligned, unlike their dependencies on MS/Adobe/Motorola/IBM/Intel.