We need something that even senior citizens can use to replace Windows XP on a system they can't afford to upgrade. Just the basic word processing Internet surfing and email.
ReactOS is progressing as well.
OSFree the OS/2 rewrite seems slower but using the M4 kernel with DOS and OS/2 personalities.
My personal experience from large scale transition from Windows 7 to Linux Mint at work indicates that people ABSOLUTELY can use Linux - the UI is (unlike Win10) stable and things do not move around, settings don't change themselves on upgrades. And, importantly, updates can be set to be silent and automatic.
I am probably one of the biggest naysayers of Linux as a desktop platform, so keep that in mind when I ask: What's wrong with Linux for this use case?
If all you need is an internet kiosk, Linux is fine. In fact, I'd go so far as to say that's been the Linux Desktop's targeted use case for about a decade now because their cultural attitude is that anyone who isn't a C greybeard needs to be bottle fed.
My other grandmother has been on Chome OS for almost as long. Which has been another great option. I do wish that Google had better support for installing/running full Chrome OS on more generic hardware. I find it's just about the best option all around for the novice computer user.
The way I see it, it is nostalgia. Which has its value. For ReactOS, it also provides backwards compatibility and essentially is a FOSS and free as in beer Windows implementation. However, there are also progressive OSes such as Nix, Tails, Qubes to name 3, or microkernel-based OSes. These are where the innovation lies.
They have something that boots, but I am not sure if it can run OS/2, DOS, Windows code yet.
I wanted to donate $5 but their donate button is broken.