And before you know it you've built a very complex, and not very secure, operating system.
Also, this argument only works if you just broaden the definition of “OS” to “anything that runs that isn’t your apps”.
Sounds like Plan 9. Which would put that around 30ish years ago. Mainframe OSes can probably make similar claims even earlier.
Not that many people keep large distributed workloads anymore, and SLURM-like schedulers on top of regular operating systems were deemed good enough for supercomputers.
The Cray T3D had a really nice distributed services model (really kind of a distributed exokernel) that would be worth emulating
on some machines there was an interactive ganged run facility like 'mpirun'. I think even this distinction where there are 'login' or 'service' nodes and anonymous runners would be at least a little structure. I guess you could argue that k8s is this, but it kind of falls short and seems to require a lot of continuous propping up.
I worked on a single system image project that didn't ever get shipped. it turns out that a syscall proxy layer isn't that difficult to implement, and that leaves you with an undisturbed user space.
anyways, there are a whole host of design options that don't look like k8s or slurm. and having spent some time recently on non-hyperscaler clusters, that bottom level of bringup (provisioning, networking management, reporting, fault tolerance, distributed filesystems) is really a nightmare. I think we lost a lot of traction there by raising generations exclusively in someone else's operational context.