I'm not sure, I think this is ungenerous and cynical. I think if you were to seriously evaluate people on a large scale for burn out, you would find that it is more common, across more professions, than is commonly accepted.
There is probably a bottom tier of practitioners who are marginal, and their successes will be more randomly distributed due to fortunate or unfortunate circumstances. The unfortunate people in this group will be difficult to distinguish from the incapable-but-hanging-on-anyway.
That said, I suspect that there is also not that much difference between the symptoms of being burned out and of never having been capable in the first place. I also am not convinced that all burn-out is reversible. Even if you recover your full mental and emotional strength, the experience of deep burn-out can really change a person. You can never get back time that you lose.
There is probably a bottom tier of practitioners who are marginal, and their successes will be more randomly distributed due to fortunate or unfortunate circumstances. The unfortunate people in this group will be difficult to distinguish from the incapable-but-hanging-on-anyway.
That said, I suspect that there is also not that much difference between the symptoms of being burned out and of never having been capable in the first place. I also am not convinced that all burn-out is reversible. Even if you recover your full mental and emotional strength, the experience of deep burn-out can really change a person. You can never get back time that you lose.