Here is one major reason: I have read that Guido van Rossum rejects all CPython patches which simply improve performance, because he thinks Python is "fast enou

Here is one major reason: I have read that Guido van Rossum rejects all CPython patches which simply improve performance, because he thinks Python is "fast enough" and is unwilling to make the code more complex / risk the introduction of new bugs just to make Python faster. In contrast, the Lua developers always cared a lot about efficiency, not just speed, also memory use, and even GC pause times. They simply have different priorities than the CPython developers.