> They need some form of locking around Python objects accessed from multiple threads, since Python has no ownership model. "Ownership models" are not a given.

> They need some form of locking around Python objects accessed from multiple threads, since Python has no ownership model. "Ownership models" are not a given. C++ has no "ownership model" and it doesn't lock around objects. Multi-threading users are just given the synchronization primitives and are expected to manage their own solutions. The same is true in Python: https://docs.python.org/3/library/threading.html#lock-objects https://docs.python.org/3/library/threading.html#lock-object... - in fact, if you're using objects simultaneously from multiple threads without using some sort of locking scheme, you're probably already in trouble... The main thing that's keeping the GIL around is the reference-counting garbage collector. If your python implementation uses its own GC mechanism, it doesn't have this problem.