There are literally more billionaires on HN than people in the US who could write "Axiomatic Characterization of Ordinary Differential Cohomology."
Apparently some folks are motivated to strive towards those statuses. Not quite my cup of tea, but I wouldn't discourage them or say those goals are flatly impossible.
Or do you mean just maybe understand the general essence of the paper's title, and understand major contributions after spending some time reading the paper?
If the former, well... yes. That's probably true for almost all significant research, especially in mathematics.
If the latter, I think you're probably wrong. And that's not to trivialize the work presented in the paper; if anything, the contrary -- the paper's actually quite well-written.
Counting up the number of people who could've written a given non-anonymous paper is pretty unheard of in academia afaik. The answer is usually politely assumed to be "exactly the number of authors". I've certainly never seen this behavior. So I'm not sure your answer is actually at all clarifying.
Probably, and this is just a guess, neither Simons or Sullivan claim they could've written the paper alone. And it's certainly impossible to write essentially the same paper without plagiarizing. So probably there are either zero or two people who meet the "could've written this paper" criteria.
So, why didn't you just say "there are more than zero/two billionaires who read HN"? Seems less round-about.
Nothing is impossible, but it comes down to probability. The probability that you will become a billionaire is quite slim. However, the probability that you can retire early or make close to a million or so is exponentially higher.
Apparently some folks are motivated to strive towards those statuses. Not quite my cup of tea, but I wouldn't discourage them or say those goals are flatly impossible.