There are probably no 10x engineers, but I'm quite sure there are 10x teams. Better to focus on growing one of those than chasing a fairy tale.
Still, it really fed into the "only hire the absolute best" mythos that has spread in countless other harmful ways. Consider the aphorism "A players hire A players, B players hire C players".
The general message of all of it has always been: "You must hire the very best, even one merely good employee will poison the well and ruin everything".
Yet hiring practices are, as I said already, imprecise... which creates all sorts of bizarre behavior in the attempt to snag the "very best".