https://www.theregister.com/2023/07/18/linux_desktop_debate/
It would be twice as much if people could stop arguing about who counts and who doesn't
Not mine but sounds like a showerthought to me. TL;DR ChromeOS is the “wrong” version of Linux and has 4% while GNU/Linux has 3%
Wikipedia is using this site as the source, and that site shows around 20% market share for Mac. Linux is at 3% and ChromeOS is at 4%, so if you combine them and double that it still isn't at 75% of the market share Mac has.
This isn't mentioning that dealing with Linux compatibility is more annoying than Mac or Windows compatibility. Macs are very uniform, Windows has a giant making sure everything is compatible, and Linux has 900 distros that will never agree to co-operate.
Windows is also ridiculously good at backwards compatibility. Mac frequently just breaks old software and Linux is largely unconcerned because they assume anyone that cares will find a way. That backwards compatibility is over of the major keys to Windows success with developers.
But Linux is good at backward compatibility tho. Linus Torvalds leadership made sure that very few if at all any changes to the kernel will break existing userland. This means that if you have a program with their needed dependencies in the right version (which is easy with docker/flatpak/appimage) your programs will run flawlessly even if they are from the 90s.
I'm pretty sure that's just default userland and foreign packages still update frequently and kernel updates might've broken syscalls not used by default userland.