Adding to some of the other comments - I think this is a hard area for a new OS to take hold currently. It's taken almost 35 years for Linux to get to where it is today - which is STILL a niche on the desktop, despite server dominance. (I say this as someone who has been Linux-only since 2007 (edit: not 2023 lol WTH was I thinking) at home)
With that in mind, if I were contemplating a choice between making a new OS or devoting my efforts to improving one of the others (to be clear I don't have the skills for this to be an actual choice), I don't know what might drive me to create a new one.
Adding to some of the other comments - I think this is a hard area for a new OS to take hold currently. It's taken almost 35 years for Linux to get to where it is today - which is STILL a niche on the desktop, despite server dominance. (I say this as someone who has been Linux-only since 2007 (edit: not 2023 lol WTH was I thinking) at home)
With that in mind, if I were contemplating a choice between making a new OS or devoting my efforts to improving one of the others (to be clear I don't have the skills for this to be an actual choice), I don't know what might drive me to create a new one.