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 make a similar argument for why there isn't anything comparable to the Beatles at the moment.
The other thing is, that there is not much of basic math and physics left anymore for people to study and figure out something new.
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.
I'm not saying that it's finished as in there-is-no-more-math-to-discover, I'm more saying that all the math at elementary-to-high school level is pretty much finalized, and kids will probably never learn about Chris Havens, even though for what he did, he probably needed to be a bigger "genious" than eg. Archimedes. Students at math courses, sure... but they learn about many mathematicians there, and most of them are not known by the geneal public.
They just don't all have a deep, cultural impact on the zeitgeist.
I think this is especially true in the sphere of art & culture. The enormous variety of work being churned out by artists and creators-- combined with such easy access-- means that something truly groundbreaking won't be seen by as many people because those other people are drawn to other content, equally incredible, that appeals more to their own interests, making it much harder for something to break through siloed interests to the zeitgeist.
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 make a similar argument for why there isn't anything comparable to the Beatles at the moment.