This could actually happen soon. Outside of office use most casual users in younger generations are using laptops. Desktops are getting to be more niche and associated with computer builders and power users. As Windows gets shittier, Linux gets easier to use and customize, and desktop use shrinks to just enthusiasts, we could very well see Linux on the majority of desktops.

I’m about to do this for my mother as well. I just switched back myself and found Mint has come a very long way. The last time I ran it as my main OS 10 years ago it was pretty demanding from the user, but mint now is probably more user friendly than Windows.