(...just a theory...)

I've always felt that "Genius" was in the creation, not in the perfection of that which has already been created. (For example, the genius is the one who first figured out how to determine that 2347x435=82145.. the one who figured out the "formula", not the one who can, using that formula, figure out that 2347x435=82145 in the least amount of time.) "Genius" is often interpreted as "madness" because of that. The "Genius" expresses concepts that are new... unlearned... often outlandish to the majority. A "Mad" person is often called an "idiot".