I'm a good counterexample to that story though. I've started coding when I was nine, have Masters in Computer Science, have worked in software for roughly 15 years (most of that coding). I've taught myself linear algebra, 3d computer vision/vSLAM from scratch, computer graphics (incl. more advanced concepts like PBR, Mesh Shaders etc.), statistics and machine learning, and probably other things I'm forgetting now.
However, in the end I chose not to do anything with that knowledge and that interest, and work relatively simple back-end jobs. Why? Because, no matter how hard I try, I can't put in more than 15-20 hours of hard focus per week. If I try to push myself harder, I just crash (sometimes even after two days - I get intense headaches on day three and my experiment is concluded). I've tried it probably dozens of times, and the results were always similar - if anything, it got worse with age (I had more energy in my twenties than now in my fourties).
However, in the end I chose not to do anything with that knowledge and that interest, and work relatively simple back-end jobs. Why? Because, no matter how hard I try, I can't put in more than 15-20 hours of hard focus per week. If I try to push myself harder, I just crash (sometimes even after two days - I get intense headaches on day three and my experiment is concluded). I've tried it probably dozens of times, and the results were always similar - if anything, it got worse with age (I had more energy in my twenties than now in my fourties).