Rust is possible and proves that you don’t need "optimizations" to optimize, but that optimizations are actually possible. Now that's kind of irrelevent for most of the article focusing about constant versus variable time which is not really an "optimization" problem but already an optimization one, but at least putting appart this rust proves that a langage doesn't need to allow nasal daemons to get good perfs. You just apply the technics when you actually know they are correct, not when you speculate the existence of the mythical perfect programmer (where this hypothesis has actually be disproven by studies on the subject)