Besides the internal politics, I think the greatest blocker with improving python performance is not giving whomever is running the code any control. If I don't

Besides the internal politics, I think the greatest blocker with improving python performance is not giving whomever is running the code any control. If I don't use any naughty C plugins, or if I can assure you that I've annotated all my types and can allow a large class of optimizations, why can't I run my code with some VM flags? It's one language, but why can't I tune my VM to my needs? I can't imagine Java not letting users tune their GC.