Thats an interesting issue you have raised. Let me first answer in relation to politics and then in relation to academia.
In politics, I think lack of expert knowledge is very common occurrence yet it does not seem to stop anyone from being successful in that field. There are so many examples in politics of someone who has had a midlife crisis or a whim or whatever and one day decided to become a politician (the governor of California is the first to come to mind). I don't know if this is a good or a bad thing about the American political system since on the one hand it prevents politics from being a exclusive cadre for the wealthy elite but on the other it puts enormous power in the hands of people who may not know how to exercise it properly.
In academia, I think there are some areas that are called sciences where interesting opinions and elegant verbal and writing skills can get someone really far without much factual or objective basis for their opinions. I guess there are really two different issues you are raising here. One is: does having an extraordinary mastery of a scientific field is necessary to publish in that field? The second is: does having insight and shrewdness in a "non-scientific" field can ALONE allow you to be successful?
I think the answer to the second question is definitely YES and in fact many of the "non-scientific" areas of academic rely
on elegant speech and writing as the basis for their work. I think the answer to the first question depends on what nonscientific area we are talking about. Poetry and literature are examples of areas where any layman can achieve fame and academic repute without really knowing anything "academic" as long as their ideas are revolutionary enough. On the hand, the study of history really requires you to know A LOT about your era if you want to make a significant contribution.