I think what the author is missing here is how does he define "succeeding" in the field. It sounds like for himself anything short of "theory of everything" is

I think what the author is missing here is how does he define "succeeding" in the field. It sounds like for himself anything short of "theory of everything" is failure, but for others, finishing a PhD is success. So on his terms for himself, terms even his advisor is way short of that goal. Heck, even Einstein was. But then he sees others just completing an arbitrary thesis and thinks of them as the successful ones. The author has just failed to reconcile his expectations and hopes of himself with what he's seeing others do. In other words, I think even if the author had "succeeded" to the point of being top in his class and exceeding the research output of his advisor, he'd still be unhappy, still consider himself unsuccessful. Opting out was probably the best decision he could have made, and his life is probably more productive thereby. And heck, maybe he even still has a better chance of finding some theory of everything via some analogy he comes across in his day to day work than by a life of research in "fiber bundles".