Because normal people don't even really understand what an OS is. For a layman, it is esoteric, arcane knowledge. My wife is not a technical person. She wouldn

Because normal people don't even really understand what an OS is. For a layman, it is esoteric, arcane knowledge. My wife is not a technical person. She wouldn't know what Linux was or even that it existed if I never told her. Much less how to install it, what benefits it has in relation to Windows, etc. For her, if her computer is slow, it is because it is old or broken, not because the OS is a pile of crap. Beyond that, switching OS can be a major endeavor. I wanted to switch to Linux years before I took the plunge 3 years ago, but many things (including inertia) held me back. It was when I was going to do one of my yearly fresh windows installs that I decided to "let me give Linux a shot, if it doesn't work I do the fresh Windows install later". Linux worked well, and now I am here.