A symbolic moment, this: in Q4 2013 the number of computers* sold by Apple was larger than the number of Windows PC sold globally. If you add Windows Phone to the mix they're more or less exactly equal.
This is a pretty good illustration of the scale of mobile: Apple limits itself only to the high end of the mobile market but still sells more units than the whole PC industry.
Note “scale of mobile” more important than Apple v. Microsoft. The mobile personal computing market simply dwarfs the PC market.