Python is difficult to optimize due to complex language semantics. This excellent talk describes how the semantics of the "add" operation are much more complex

Python is difficult to optimize due to complex language semantics. This excellent talk describes how the semantics of the "add" operation are much more complex than generally described. a+b is not just a.__add__(b), you have to read 200+ lines of CPython interpreter code to fully resolve its semantics: https://youtu.be/qCGofLIzX6g https://youtu.be/qCGofLIzX6g Not saying it's impossible, but it's more of an uphill battle than optimizing other languages that have more regular semantics. Python is also constrained by its C API, which is a very low-level and exposes a lot of implementation details to C extensions. Changing the API could improve performance but it would also make Python incompatible with a large ecosystem of C extensions. I sometimes wish for Python to define a new C API that exposes far less, and to begin a long-term migration towards the new API so that eventually the interpreter would be less constrained. It would be a large migration, but unlike Python 2 -> 3 it wouldn't affect everyday users, only extension authors. I don't know if it will ever happen, but a person can dream.