[smnrchrds]

IIRC, on of his reasons was that CPython works on a large set of architectures and OSes and it's impossible to write a JIT that works on all of them. JITs usually support only the most popular architectures(x86 and x86_64) and CPython wants to remain as architecture-agnostic as possible.

[fijal]

That's a bullshit argument and I don't think it was raised. You can always run JIT on a subset of architectures (ARM, x86, x86_64, PPC and MIPS really cover a lot) and run interpreter on others.

The argument was always "easier to maintain", but that said, unladen swallow was agreed to be merged into cpython, had it met it's goals.