While the OP talks specifically about Python, the patterns of a semaphore, lock (aka mutex, a semaphore with value 1), condition and queue are relevant to many languages, many of which are not hampered by a GIL. Personally, the more I use threads, the more I like this way of programming, at least for the request/response paradigm.
That is an entirely different problem than the one I typically face. Also while I have no experience writing OS's, but IIRC none of the modern ones have their processes based on event loop. Maybe writing an OS is just not a trivial problem and the code is bound to be somewhat ugly.