I've done work on a proprietary embedded RTOS that has had high level versions of those barriers at least a decade before the C atomics model was standardized (and compiles them to the closest barrier supported by the target architecture).

I suspect that the OS and Architecture communities have known about one-way barriers for a very long time, and they were only recently added to the Arm architecture because people only recently started making Arm CPUs that benefit from them. And that seems like a more likely explanation than them having been plucked from the C standard.

Moreover, one-way barriers are useful regardless of what language you're using.

Note that I am specifically pointing to those exact barriers, and not "any old barriers". C's memory orderings don't really lower down to a single instruction on any other platform that I'm aware of because of subtle differences in semantics.