The group success is due first and foremost to the filtering of a variety of solutions achieved through evaluation. When none of the answers initially proposed is correct, then all of them are likely to be rejected, wholly or partly new hypotheses are likely to be proposed, and again filtered, thus explaining how groups may even do better than any of their individual members.
Maybe that explains why Wikipedia is usually much clearer to read (IMO) than professionally produced encyclopedias.
From the Why do humans reason paper: