realistically the increased expressiveness of Python lets the PyPy devs opt into optimizations the CPython devs find out of reach Not really: It's the compilat

realistically the increased expressiveness of Python lets the PyPy devs opt into optimizations the CPython devs find out of reach Not really: It's the compilation strategy (that whole meta-tracing JIT compiler thing, compared to a simple bytecode interpreter) that makes the difference, not the surface syntax of the implementation language - which is actually not 'real' Python, but a restricted, less dynamic subset known as RPython. Also note that the CPython is deliberately kept 'dumb'.