He's referring to the competition between Apple's Mac & MS Dos + Windows in the late 80s to mid-90s. The compressed version of the narrative is:
Mac was innovative, brilliant, early but too expensive & without enough applications.
Windows was late, copied & sucked but was cheaper (because of commodity hardware) had all the dos apps from the 80s and got gradually better. By 95 the network effects of the developer ecosystem had locked windows in to 20 years of dominance. It also helped that by 95 windows didn't really suck much.
The moral of the story is (supposedly) that OS Platforms have one winner. Developers develop for the largest user base and users buy the cheapest platform with the most apps.