Most startups probably start as a cocktail party idea, so although the author is correct, he underestimates the value of the concept.

Also, whilst it is intuitive that someone without expertise in a field is easy to get everything wrong, it is more interesting that often experts also get everything wrong. Sometimes this happens because the problem may affect an expert's field but belongs to another field, or the problem just exists from someone else's point of view.

In Greece we refer to people who always know everything better than experts as couch coaches. :)