Well if Tim Cook says so then it has absolutely nothing to do with low (labor) costs. It must be true that it has nothing to do with cost and he is a totally unbiased and 100% credible source for making such assessments. To his argument's credit, I don't think China has been doing a poor job of manufacturing iStuff.
Source on Occam's razor being anything more than a philosophical framework? Kind of silly to even bring that up in this scenario without looking at the possible motivations or lack thereof.