The process to install Ubuntu vs Windows is pretty much the same.
Create a user, choose a timezone, connect to Wi-Fi or LAN and wait for setup to finish. It is not complicated by any mean.
As I mentioned, most people never install an OS in their life, so they don't know how to create a boot drive and install an OS.
So the issue isn't that installing Linux is complicated, it's that installing an OS on an empty drive is not a thing that the vast majority of pc users has done or will ever do.