I read the article. I disagree with the premise that there are fewer geniuses today. There are plenty of geniuses, if not more than ever. They just don't all have a deep, cultural impact on the zeitgeist. Take for example the resolution of Fermat's Last Theorem and Poincare's Conjecture. Or the work being done on the Twin Primes problem. This article is probably better situated as an examination of culture. You could…
Archimedes' buoyancy, newtons laws, etc. are all something that we know and learn about in elementary and high schools, and we remember their names, because they were either first to figure it out or more realistically, first to put it in writing in a way, that we can now use in "math/physics". Since the elementary to highschool curriculum is limited, we learn only "basic" stuff there, and most of that was attributed to historical physicists/mathematicians.
Now, in modern times, it is hard to invent anything "by yourself" (you need to work at a college and/or institute, to get access to proper equipment and mentors), and even when you discover something new, the discovery is so far away from "basic" math/physics, that the only ones who read the article and understand it are other mathetmaticians and physicists, kids will never learn about you, because the science is too advanced, and even when something attracts the mainstream media (to make you famous), the media then published that "scientists prove good exists" (the famous "god particle"), or worse.