Until Linux is as easy to use as windows, DL, click, install, run, or an alternative comes out that does make it as simple as that windows will stay on top.
That's why windows sold. Command based os wont reach the masses these days. I have a good knowledge of PC's and how to use them but getting ubuntu to do what I wanted was a chore.
Ease of access and familiarity is windows biggest selling point over other os.
All those gamers who bought windows for gaming also bought it to use as a pc. I doubt gaming whilst a big factor for a lot of gamers was as big an influence in windows success as you think. Windows was already the number 1 os before gaming took off on the PC.