I'm not 100% sure you're being literal but I agree with this statement when taken at face value.
Being "extraordinary" often means you're just making somebody else richer. There are some objectively extraordinary folks working at e.g. Facebook, but what does that really gain them? What has that given the world? It's a mixed bag, to put it mildly.
Probably the only real reason to strive for being "extraordinary" at your career so that you can stop working for other people, or if the craft itself brings you more joy than anything else in life.
I think it's unfair that "mediocre" is seen as a bad word. We have so many things to do, I think it's perfectly good to be mediocre in many ways. We're competing on a global scale, it's impossible to be exceptional on many dimensions.
I'd like to encourage more people to be happy being mediocre.
It's also true that even a "mediocre" engineer is elite in many ways - they are "mediocre" compared to all the other folks who managed to carve out a sustained engineering career. However, even somebody in the middle of that group has elite engineering skill relative to the population at large.
This is true of many careers, of course!
I always feel bad for the professional athletes who "suck." It's kind of hilarious -- even the "worst" professional athlete in a given professional sports league is actually an extremely elite specimen, with only a tiny fraction of all athletes even being able to make it into such a league.
When i first joined my cycling club, i was dead last every ride. Even then i used to say "i'm faster than all the blokes who were too lazy to get out of bed". Slowly i got a bit better. Reminding my self of that was a great motivator.
Hah! I do the same with tennis. I'm not very good, but you know... I can do some decent things out there sometimes, and I'm proud I took up the game in my 40s after so many of my peers have totally given up on such things.
I'm also blind in one eye. Probably not a lot of people out there playing tennis with just one good eye. Perhaps I actually am "elite" in terms of half-blind, middle-aged, overweight, novice tennis players.
Being "extraordinary" often means you're just making somebody else richer. There are some objectively extraordinary folks working at e.g. Facebook, but what does that really gain them? What has that given the world? It's a mixed bag, to put it mildly.
Probably the only real reason to strive for being "extraordinary" at your career so that you can stop working for other people, or if the craft itself brings you more joy than anything else in life.