Most people's reasons in my experience demonstrate to me that they have a perception of Linux as it was 15+ years ago.
I discussed switching to Linux with a group of friends in a voice chat some time ago, most were fairly open to it, and one or two have switched since, but mainly their reasons were time constraints, not wanting to go through the process of backing up files, and finding alternative software.
One guy in particular brought up gaming, MS office, and some other particular software they used. I showed them protondb and every game they looked up was gold or higher, showed them libre office which they could not complain about since it generally works a lot nicer, and it turned out that other software was available as a .deb. After all of this, the reason they gave me was "but I like Windows".
Fair enough I guess, though they couldn't really produce the reason as to why.
Generally, people just don't like any kind of change, even if it has the potential to make them a lot happier.