Every place has had some experience with some problem that entire different teams, with dozens or even small hundreds of people failed to solve for years and years, and then some individual came and did it.

And almost everybody has seen or heard some similar story.

The thing is, those stories don't have a lot of similarity to each other, and there isn't much you can conclude for anybody's competence without looking at all the details. But they happen all the time, and not only in software development (just not on the same frequency, for obvious reasons).