I don't think it's one or the other rather both. TSMC is definitely starting to lead the foundries but e.g. nobody expects the next gen Qualcomm Snapdragon chip to beat the Apple A12X even though both are coming out of TSMC.
IMO Intel is lagging on both fronts, AMD is catching Intel a bit, ARM is steamrolling year/year perf increases compared to x86, and Apple remains +25% ahead of every other ARM chip.
This is TSMC vs Intel. TSMC basically make the 7nm chip for Apple and AMD.
It looks like this company HQ at Taiwan provided the bragging right for Apple and AMD…