Cost isn't only money. In the case of linux it is time to learn to use it (which is a sunk cost on windows: already paid it). Then you need to download and install it - again windows comes by default so a sunk cost.
If somebody else admins your system. However if not there is a lot to learn. At least every distribution I've used needs manual updates from time to time. (though admittedly most people would replace the computer before I've seen anything hard happen)
Windows user here. It goes vastly further than that. I've been using Windows since version 3.0. I'm used to it to the point where it's second nature. Linux is foreign and difficult to comprehend, not least because it explicitly avoids being anything like Windows or accommodating habits people acquired from Windows. I don't like the direction Windows is going any more than anyone, and I'm avoiding Windows 11 for the time being, but as long as Linux people continue to believe that the only reason Windows users don't switch is because they don't know Linux exists, Linux will not be able to attract Windows users even as Windows goes full capitalist enshittification.
