Comment by v3ss0n

Because it is one of the most ambitious project in opensource world and very little is known about that. It is neglected by Python Contributor community for unknown reasons ( something political it seems) . It was developed as PHD Research project by really good researchers. PyPy had written python in Pure python and surpassed performance of Python written in C by 4-20x . They delivered Python with JIT and also Static RPython : which is subset of python which compiles directly to binary. I had also personally worked together with some of the lead PyPy developers on commercial projects and they are the best developers to work together with.