Every new Windows version, or even Service pack...people say this.
Interestingly, very few do this.
Agreed, very few do it. For many it's a disruptive process to switch. But enough do it and the vast majority of them that do take the plunge stay. Windows doesn't have much to recommend coming back, it's all third party applications at this point. That's all Windows has now.
Realistically, "very few" keeps adding up. There was "very few" at Windows XP, plus another "very few" at Windows Vista, .... (rinse repeat) is why Linux is a growing user base. Microsoft keeps bullying people - they refuse to learn. Linux right now is around 2.5% according to StatCounter and has never been bigger looking at long term trends. Several years ago, it was 2.0% even. Several years from now it will be 3.0% and even probably 4.0% thanks to Valve. Go back far enough to 1991, and Linux had a grand total of one user on one computer.