TLDR: Is it reasonable to expect mere morals to have mastery over every facet of the development stack? No it is too much for mere mortals My Answer: Is it reasonable to expect mere morals to have mastery over every facet of the development stack? Yes, it is called 4 years min. of a CS degree, and then continuous studies in multiple areas... like any other respectable professional
I have no formal training of any kind and have been developing web based applications for the better part of 18 years now. In my experience, a C.S. degree provides absolutely no guarantee of mastery of any portion of software development, let alone a full-stack.