Switching costs! I suspect there is a high degree of knowledge and experience you posses that you are discounting. Most people would need to learn a really tremendous amount to understand what they were switching to and why. Hell, I've got enough know how that I could figure it out, but it doesn't rise high enough in my priority to do.
You might also be discounting people who use their machines to play games with. Although I hear good things about SteamOS, that might push the needle.
In my opinion, switching costs are real and are a problem. I've especially seen it with the elderly.
However, different Windows versions now have not-insignificant switching costs as well. So while I agree that it is a concern, Windows users must deal with switching costs every three to five years whereas KDE users have had to pay those costs exactly once (KDE 3 -> 4) during the almost two decades that I've been using KDE.
From my experience with family, coworkers, friends, and neighbors, the vast majority of people today need a web browser. That's it.