Is that really the case for software? I mean, I'm very skeptical of the "only the best and brightest" nonsense, as I think it selects for the wrong people. But I'm also skeptical of the "eh, good enough" heuristic.
Right now I'm helping a friend deal with a code base that was built by an outside dev shop. It undeniably works; the business has been running on it for a number of years. And honestly, like most software, it's not a complicated app; mostly CRUD stuff. But overall it's a spaghetti snarl. Any given concept might be in the code, or in a config file, or driven by SQL data, or even driven by JSON blobs stuffed into the database, mutated by the main code base, and passed along to the JS front end.
Now that I can see the code, I understand why the dev shop needed so many people working on it, and why all features were hard to do. It's because when you use a lot of mediocre programmers, they all create work for themselves and one another. Not intentionally, but just because they aren't able to see how the differing approaches and sloppy work slowly diminish productivity.
So although I agree with you that a lot of companies hire on vanity metrics, I'm really skeptical that "whoever, as long as they barely qualify" is a better approach.