Not only is Linux on desktop "ready", it's been parent-proof for a long time. Sometime around 2012, Windows XP started having issues on my parent's PC, so I installed Xubuntu on it (my preferred distro at the time). I told them that "it works like Windows", showed them how to check email, browse the web, play solitare, and shut down. Even the random HP printer + scanner they had worked great! I went back home 2 states away, and expected a call from them to "put it back to what it was", but it never happened. (The closest was Mom wondering why solitare (the gnome-games version) was different, then guided her on how to change the game type to klondike.)

If "it [Xubuntu] works like Windows" offended you, I'd like to point out that normies don't care about how operating system kernels are designed. Normies care about things like a start menu, and that the X in the corner closes programs. The interface is paramount for non-technical users.

I've run Linux almost everywhere (work machines excluded) outside of my main desktop/gaming rig for over 15 years, up until a year ago when I switched my desktop. My last Windows install is on my retro PC (98SE), and it'll stay that way, because changing that would ruin the nostalgia.