If you have to install an OS, you fail! Most people use what comes on the machine. This is why Windows struggled to get traction until 3.x: Windows 3 was the first version for which Microsoft negotiated OEMs to preinstall it. This is why Linux struggles to get traction today. Preinstalls are key.

If my wife had to install an OS before using a computer, yeah, I think she could do it. But she'd find it such an incovenience compared to her Mac, which came with the easiest to use modern OS all ready to go out of the box.