For web dev, I would rather have an expert in rust obviously, but I would also rather have an expert in php who expressly choose php over rust for the sake of the kiss principle. Plus he would probably be satisfied with a lower starting salary :-)

But you are right, reality often goes differently than what's thought to be ideal, which is why "perfect" solutions sometimes doesn't gets adopted in favor of a less perfect solution, which leaves the old "perfect" solution forgotten by history.