Good argument. But then by the same argument, would you not trust Sal Khan's Khan Academy videos, since he himself has experience in only a few of the many are

Good argument. But then by the same argument, would you not trust Sal Khan's Khan Academy videos, since he himself has experience in only a few of the many areas, he researches & then makes educational videos about. I would tend to agree with you : as a rule, people need to be experienced in a discipline/area to produce high quality content in that discipline/area. People like Sal Khan are the few & rare exceptions to this rule.