Performance is one part of the discussion, but cleanliness is another. A Python4 that actually used typing in the interpreter, had value types, had a comptime phase to allow most metaprogramming to work (like monkey patching for tests) would be great! It would be faster, cleaner, easier to reason about, and still retain the great syntax and flexibility of the language.

I’ll be happy if over night all Python code in the world can reap 10-100x performance benefits without changing much of a codebase, you can continue having soup of multiple languages.