This special casing just had not been implemented yet. But as it is an interesting optimization, more so with multi-interpreter or no-GIL Python, the developers

This special casing just had not been implemented yet. But as it is an interesting optimization, more so with multi-interpreter or no-GIL Python, the developers will actually introduce immortal objects in Python 3.12 to avoid counting references on some objects (PEP 683 has been accepted): https://peps.python.org/pep-0683/ https://peps.python.org/pep-0683/