Micropython is an interpreter, implemented in C. Anything running in it wouldn't be an operating system in the sense that we usually mean. Anything incorporating it wouldn't satisfy OP's goal of being "only Python".
If a CPU were developed that used Python bytecode as its official instruction set, perhaps using micropython implemented as microcode, then it might work.
I don't. Those fields are but small slivers in the realm of technology, and they're not even particularly novel any more. A community dedicated to one or both of them might make sense, but there's no reason to let them dominate the technology community.
I agree with you there.