While sometimes overruling he's completely reasonable here. There had been multiple approaches to jit-ing emacs bytecode, and all of them offerred a very limite

While sometimes overruling he's completely reasonable here. There had been multiple approaches to jit-ing emacs bytecode, and all of them offerred a very limited speed-up. Jitting engines bring extra dependencies and one more layer of complexity to the C core of the editor. And not too many editors support a full language of their own. Notice that Emacs is mostly a volunteer effort and the resources are very limited. For example this particular engine seems to offer a good speed boost on numeric operations but one of the replies mentions that realistic complex code is sometimes slower than a pure byte-code VM. Probably a bug but still... After all those failed attempts certain level of scepticism is understandable.