Where have you lived for the past 20 years? Almost all PC laptops and desktops (from Dell, HP, IBM, Lenovo and others) have had Windows installed as the default option for that time. Sometimes you can uncheck it and save a little money, sometimes is won't save anything and most of the time you don't have the option to remove it.

The innovation has been to install vendor garbage in addition to Microsoft garbage. So it takes even more effort to get a clean system.

Only in the last few years has some distro of Linux started being an option.