This hits us hard. I would love to deploy almost everything we do on pypy, but legacy code dictates the use of C modules that don't have pure python implementat

This hits us hard. I would love to deploy almost everything we do on pypy, but legacy code dictates the use of C modules that don't have pure python implementations that come close to the necessary functionality. Compatibility with the massive ecosystem of existing code is something everybody who says "just rewrite the runtime with X" seems to forget.