Well, the mathematical genius asks only 20$, but you should understand that he focuses only on a niche: the mathematics niche.
On the other hand, OP answers to
any question, thus his area of expertise is way larger. He had to study a lot, in order to know
everything. And now comes the payoff, right?
With other words, as some mean people used to say: the generalist learns fewer and fewer about more and more subjects, reaching in the end
to know nothing about everything, while the specialist learns more and more about fewer and fewer subjects, reaching in the end
to know everything about nothing