Word is out there, if we are discussing the Linux kernel - all those Android devices for a start...
I highly doubt very many people who have an Android phone know about the kernel underneath.
Add to that they have no real control over it either. You buy a Samsung Galaxy S6 phone, you get what you're given and most people are happy enough with that.
If you were to say, "hey, you know that phone you like so much, you can install that OS on your desktop computer!", their likely reply would be, "what? why the heck would I want to do that?!?"
And they'd be right.
However, my guess is that we are discussing a (generic) Linux Distribution - the kernel, the libraries, the applications, the user interface, the package management system, etc.
Yep, and there really isn't a "generic Linux" for people, there are just too many versions and flavors. It is confusing, and frankly people don't like that much choice. It requires they understand the computer more than they want to.
This is why when you go to buy a car, few cars offer more than trim levels and a handful of options. You can get that Ford Explorer in XLT, Limited, or Sport, take your pick. A Honda Odyssey comes in LX, EX, EX-L, Touring, and Touring Elite, pick one. That is 5 choices, probably 1 too many, but there it is...
On average, people want a "cheap, middle, deluxe" option... "Small, medium, large... maybe extra large"... Linux is WAY too fractured for Joe Consumer.
For a utility machine - web browsing, email, the occasional document or spreadsheet - several Linux Distributions work great.. but there is no commercial push to them.
Of course they do, I don't doubt that at all... but no one is pushing them because there isn't any money to be made... not real money anyway... Red Hat tried years ago and didn't get much traction, so they switched to supporting the business/server market and have done ok there.
Dell has tried a few times selling machines with Linux installed, and their return rates were terrible. People want to be able to install "anything", and Windows lets you install (almost) anything. You'd be really hard pressed to find a program that general consumers might use that doesn't have a Windows version.