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.
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.