So many factors concur. - Windows still has 2x the market of Apple in the US only. - Windows has lots of legacy code and architecture to maintain. - Apple users are acquainted with a learning curve, while Windows users are prone, they just want features, not quality. - Apple prices are A LOT HIGHER, if not double or triple, especially for non-US buyers. - Custom hardware makes it much easier to avoid pure bugs, because hardware predictability is a good thing for software reliability.