Non tech savvy people don't install windows or macos either. Everything comes pre-installed with the machine you buy.

If you make it to the point where you kinda know what Rufus and an iso file are, Pop! OS and Mint are easier to install than Windows.

I suppose a program could be made that partitions your OS drive and installs a distro on the second partition with a dual boot selection screen on next boot, but if you're at the point where you're curious enough about Linux to try it, you've probably learned enough to use Rufus and an iso file.

The answer is system integrators need to pre install and actively support one of the more friendly distros (like Valve with SteamOS on the deck) or it'll never catch on.

Simple users don't care what OS you present them with, as long as it's already there and it's easy to use.