Also one of the selling points of relativity in the early days was the difficulty of its math. I think it was Eddington who said that "only three people understood General Relativity."
I see your point, but if Darwin created a new field but Einstein contributed to an existing field, Darwin ought to be considered a greater genius. (Personally, I think it is better not to define anyone as a genius so that we can continue to evaluate their work critically.)
I'm saying that we value things we don't understand more than things we do understand.
I suspect that the media would indeed portray most mathematicians as geniuses, though. In fact most laypeople I know would agree that they were, and I know some fairly well educated laypeople in my opinion.
By mathematician, I mean a publishing academic with a PhD in math (or some rough equivalent to that).
That's not particularly true. I don't think there is a single mathematician whose papers are understandable to laypeople (by laypeople, I mean the average person, who remembers some but not all of highschool math). What's really going on here is that Einstein made a tremendous contribution to a tower that was already quite tall, while Darwin's contribution was to the ground floor where everybody could get on. The maths analogy to Darwin would be one of the inventors of Algebra - evolution is taught to children right along with the foundations of math and physics.