Polymaths appear to have a leg up in the genius nominations, esp. if their accomplishments are subdivided, making them even more impressive. Hence, a nominated genius might be all of the following: a novelist, science fiction author, poet, economic analyst, literary critic, essayist, journalist, historian,etc. or known as a great doctor who studied the circulatory system, the heart, arteries, veins, capillaries, etc.
I think that's why our geniuses are mostly in the past; nowadays you have hundreds of thousands of intelligent literati and doctors covering the same range of interests. Being a pathfinder is obviously different, it's harder to be the first in a field - though even then there exists the probability that in many cases the ideas are "in the air" circulating through what constituted their scientific or intellectual community.
Oh, well, just making an observation not a condemnation that this man or that woman was not "a genius" ...