Well, some people are not "geniuses" in any field, and "true calling" is just a mystical new age thing.

Being good enough, enjoying what you do, getting better if/when you can are more important. And of course, making money and creating things while doing it.

And some of those "genius" stories are just BS leadership cult. Zuckerberg, for example, was just a mediocre programmer compared to tons of regular 100K/year or less working programmers and insignificant compared to famous devs from Brian Kerningham all the way to Jamie Zawinsky, he just had the right timing, the right connections, and the ability to build a rudimentary service all the way through, which is basically what it took.