Then the mythology is worthless. The focus should then be on eliminating bad engineers, not to go chasing after unicorns. Or even more importantly, figure out why some "10X" become "0X", or vice versa.
Yes. Remember this whole thing started over 40 years ago, when management still had the mindset of large teams of factory workers and/or office paper pushers. Some were clearly better than others but for the most part, employees were supposed to be pin-compatible fully interchangeable parts, so the idea that some people could be lagging so far behind the others without management's notice was a new and novel concept. Today, not so much.