Why should they rewrite everything if it works for them?
Java/Golang/Rust/C++/C# are all about 100X faster than Python. Wouldn't it be more reasonable to use one of those than mess with the runtome to squeeze out 20% more performance?
It's absolutely not the same. The JVM uses GC for all object collection. Python uses reference counting and only relies on GC to clean up cycles.
very common in the HFT world