> but JavaScript totally missed the boat on efficient compile-ability, which is the most interesting thing about Self

That's making much use of hindsight though: the creators of Self didn't think it would run fast, until it did [0]. The HOPL paper on Self [1] spends many words recounting the challenge of making Self fast.

[0] This is arguably a stronger claim than what appears in HOPL; I think it's from a talk by Dave Ungar, I'd have to check.

[1] https://dl.acm.org/doi/10.1145/1238844.1238853