I assume people dislike those kinds of solutions because the extreme dynamism is used pretty rarely in a lot of meat and potatoes python scripst. So a lot of “regular” python scripts would have to just plaster “final” everywhere to make it as fast as it can be.

At that point youd maybe want to have some sort of broader way to signify which parts of your script are dynamic. But then, youd have a language that can be dynamic even in how dynamic it is…