This wisdom of crowds thing is really overblown.
If you give a crowd a multiple choice question with n choices, where ~ 100/n know the answer, of course the crowd will appear wise.
But if you give the crowd a question they don't know - like how to solve a bessel function, there is no wisdom in crowds.
The harder case is questions that appear difficult, but are influenced by the crowd itself, like the close of the tomorrows stock market.
also, many seemingly hard questions are easier then they look: if you don't have agred upon criteria for a correct answer beforehand, it is not clear what a good answer is.
Also, many questions relate to things that are trends that don't change much, like economic questions - say the quarterly consumer price index, which doesn't change all that much, most quarters - since it don't change much, it is easy to guess at