These mental excuses are pretty funny :-D One problem with this is that you expect a perfect dichotomy where you can isolate code which can be slow and which c

These mental excuses are pretty funny :-D One problem with this is that you expect a perfect dichotomy where you can isolate code which can be slow and which can be fast. But for a lot of code it's not easy to say in advance (pre-mature optimization plays a role too) and/or it's somewhere in the middle. We have a big Java application with hundreds of thousands lines of code. Its performance is so-so. But if you look at the profiler, there isn't a clearly responsible module/method (all obviously slow methods have been already optimized). Now it's a death by a thousand cuts. Making it in Python would make it unacceptably slow with no obvious places which could be converted into C. Writing the whole thing in C would make it a much more complex endeavor.