In football, there's only a market for the best. Nobody likes a loser.
It's the same in health. There's no market for mediocre or bad doctors.
Similarly, there's not really a market for software that doesn't work. Writing novel software that solves real problems isn't yet trivial. So there's not a huge market for bad software engineers. And there isn't yet a big enough supply of good ones to meet demand.
See why Google doesn't just lower their bar to hire more candidates. It wouldn't do them any good.