It needs to be realized that this dict implementation landed literally yesterday. There are space benefits and it simplifies the language in three places where

It needs to be realized that this dict implementation landed literally yesterday. There are space benefits and it simplifies the language in three places where we are adding ordered mapping guarantees (kwargs, namespace passed to metaclasses, and cls.__dict__, all of which were planned to be ordered prior to this dict implementation coming into the language). Before we bake the requirement of dictionaries being ordered into the language spec and require all current and future Python implementations to support it for Python 3.6 onwards -- remember, Python is 26 years old -- we want to live with the dict implementation for a few releases first.