> "Let"? Given the limited intelligence of other Earth species, I'm unsure how else operating systems would've been developed.
I suspect that you missed fhood's joke, or else I missed yours.
(It is not unreasonable to suppose that another path to the existence of operating systems would be the, perhaps human-guided, evolution of progressively less primitive programs. I am not sure that I'd want to use the result, but it's at least a conceiveable way for history to have developed.)