[laerus]

It's not like you can just "merge" pypy into python, they are totally different implementations. CPython is written in C and PyPy is written in RPython which is a subset of the python language that gets compiled, into into an interpreter with JIT support. You can actually write an interpreter for any language using RPython and their toolset, for example Ruby https://github.com/topazproject/topaz

[williamstein]

Morever, a wonderful aspect of standard CPython is that you can compile it from source on a huge range of architectures in less than 5 minutes. Building Pypy from source is more difficult, and Pypy is significantly less portable (e.g., there is no viable WebAssembly version of Pypy).