> The article says "Python has gotten nearly 50% faster in less than four years", but the original goal was a 5x speedup in the same timeframe
IIRC they originally expected the JIT to be the single focus on CPython performance improvement. But then another front was opened to tackle the GIL in parallel[1]. Perhaps the overhead of two major "surgeries" in the CPython codebase at the same time contributed to slower progress than originally predicted.