Horace Dediu for Asymco:
Note the effect in the graph above. Even if we only consider the Mac, the Windows advantage has decreased considerably, and the platform was certainly not extinguished. The new form factor Mac Pro and the continuing improvements in the thinnest of laptops shows how Mac has not just survived but prospered as the underdog which easily captures the bulk of profits.
But the bigger story is how Apple’s mobile platform has nearly reached the sales volume of Windows. In 2013 there were only 1.18 more Windows PCs than Apple devices sold. Odds are that in 2014 they will be at parity. link (emphasis mine)