Granted, Intel's supply chains probably aren't nearly as difficult as Apple's, but the supply chain is probably the least difficult part of shipping the next generation of a chip.
I wouldn't say that. From a materials and complexity standpoint, Apple has a much more difficult supply chain. But from a capital and planning standpoint, Intel has one of the most difficult supply chains out there. Every year they start building fabs that won't produce a single production chip for another 3 years, while planning on stuffing it full of capital intensive technology that isn't technologically feasible yet and might not even work. Practically speaking, Intel has to accurately forecast what Apple's, Oracle's, HP's, and Dell's sales are going to be in 5 years, a good 3 years before those companies even start their strategic and capital plans. A five year forecast for a yearly financial report at Apple might take a couple of economists a week to ballpark, whereas at Intel they probably have teams of economists, statisticians, etc. working around the year to improve their sales forecasts on horizons ranging from a week to a decade.
I think the point is that Apple's in the same league or better, and it doesn't have to compete with Intel in a fair fight. Intel has to work with every x86 program ever made (more or less) and in dozens of different environments. Apple only has to optimize its own stuff, and can change its mind on a whim.