In the abstract, it is of course fully, completely, and totally possible for a person to learn this independently or on the job. In practice, that is sufficiently rare as to not be worth discussing. Jobs where relational calculus is taught in the office are, I suspect, similarly rare.
Bootcamp skills are only useful so long as the person never needs to learn a different paradigm, learn significantly different technologies that require thinking differently, move into a different type of programming, or desires significant technical career advancement. Those things require a mix of fundamental knowledge and experience.
Does that make sense?