Is Sherlock Holmes a genius?

To decipher the messages from the Dancing Men Cipher Sherlock Holmes looked first for the most frequently occurring letter in these messages. He took this step because he knew that E is the most often used letter in the English alphabet.

When examining a crime scene one of the first things Sherlock Holmes does is to see if he could find any footprints. Footprints, he knows, can tell us a lot, including a person's height.

Detecting clues and finding out what they mean depends on knowledge already in our possession. If we did not know what footprints can tell us we would not look for footprints. If we did not know that E is the most frequently occurring letter we would not look for the most frequent Dancing Man. Now if we find enough clues we can reconstruct that structure which leave behind these clues, be that structure a crime, a secret message, or whatever. But if this is the case, Sherlock Holmes does not have to be a genius; anybody can do what he does; all we need do is make sure we know the same things as Sherlock Holmes. Take the Dancing Men Cipher again as example. Sherlock Holmes has shown us what we need to know to solve this cipher. Since he has already done this, next time we come across a similar cipher we should be able to solve it on our own. Is this not so?