As someone who came from Windows, and has used Linux as my primary OS for 15 years, and MacOS here and there (cos work provided laptop), I can tell you that Linux was not ready for prime time 15 years ago. Today, I feel it is, but definitely not 15 years ago.
With prime time I mean being comfortable enough to install it for a non-technical user. Even during Ubuntu's Unity days it didn't feel like I could install it on a computer for my parents or siblings for them to use as a daily driver.
My parents did fine with Linux. My mom still does; it's certainly less maintenance effort from me than Windows would require.
It was fine for non-technical users since at least early GNOME 2, if you're ready to help them set up and maintain. Semi-technical users (Windows power users, gamers, &c — people who like to install and configure things, but fear the deep dark abyss of the terminal) were and remain more problematic.
Unity days were the nadir of linux desktop ux — it was when Gnome 2 was gone, and 3 not yet there. Still better than contemporaneous Windows 8, though.
I can bet there’s no OS that are easy to install for a non-technical user. And that start from booting the installation media. Give someone a OS with their software already installed and they will use whatever OS that is.
People are always task-oriented, not tool oriented unless they’re nerds.
I had Kubuntu installed on my grandfather's computer for a year. I ended up replacing it for Windows because my aunt likes to install stuff on it. But my grandfather was happy with it. He only needed a working web browser and a program to use the TV tunner.
