In other professions you are not normally charged with teaching young people about a subject. An accountant does not normally teach in his or her role as an accountant. A lawyer does not normally teach in his or her role as a lawyer. Student go for particular training to become proficient in these, and other, subjects.

If someone has spent their formative years exclusively in a classroom setting their experiences of life are somewhat limited.

Going back to when I was engaged in education I found the best teachers were not the ones straight from teacher training college but the ones who had had other experiences and seemed better able to disseminate thoughts and ideas.