1. Javascript is a less dynamic language than Python and numbers are all float64 which makes it a lot easier to make fast.
2. If you want to run fast code on the web you only have one option: make Javascript faster. (Ok we have WASM now but that didn't exist at the time of the Javascript Speed wars.) If you want to run fast code on your desktop you have a MUCH easier option: don't use Python.
You could probably optimistically optimise some code, assuming it doesn't use any of the dynamic features of Python. You're going to get crazy performance cliffs though.
1. Javascript is a less dynamic language than Python and numbers are all float64 which makes it a lot easier to make fast.
2. If you want to run fast code on the web you only have one option: make Javascript faster. (Ok we have WASM now but that didn't exist at the time of the Javascript Speed wars.) If you want to run fast code on your desktop you have a MUCH easier option: don't use Python.