This is exactly what Pyodide (mentioned in the article) does, and it works great for some use cases. The problem is that downloading and wasm-compiling the entirety of CPython and all its native modules is big and slow.

A colleague of mine collected and compared a few Python-in-the-browser implementations - including Skulpt and Pyodide - with code samples and a description of the trade-offs.

You might find the write-up interesting: https://anvil.works/blog/python-in-the-browser-talk