Because it only increases high single digit each release. If they keep up the 10% improvement for the next 10 release, we will reach a speedup of around 2.5 tim

Because it only increases high single digit each release. If they keep up the 10% improvement for the next 10 release, we will reach a speedup of around 2.5 times. That's very small, considering how Python is like 10-20 times slower than JS (not even talking about C or Java like speeds).