Because C code in web assembly can translate to native machine code and still interop with Python.
All this PyObject nonsense does nothing but slowdown the runtime. V8 was built for performance from day 1. CPython is old, slow, and will always be outperformed by V8 regardless of the tweaks this team does.
I am not a compiler engineer, I can’t give you a specific, technical answer.
I was a compiler engineer, even was a committer to V8 itself via Qualcomm's codeaurora legal entity while a Qualcomm engineer, bringing up its backend code generation support to new Snapdragon processors with SIMD extensions about 14 years ago, with a coworker double checking the work on hardware targets. That said, I hope you are right, and it's fun to watch, as time will tell.
