He's saying that the math as he defines it means that YC founders who make less than even millions can anticipate making billions without anticipating doing something unsavory along the way. That's a fine, and possibly true premise.

But, in the real world, as the 'exponential earnings' stack up, the incentives to do unsavory things to keep the rate of growth scales right along with the earnings; and the odds of anyone actually 'earning' a billion dollars while sharing the proceeds and absorbing the risks and societal costs of that growth fairly, ethically, legally and honestly has a growing potential to become vanishingly small.

AOC was speaking to this reality, the author was speaking about the math functions of how some steady rate of growth crosses from a small number to a very big number due to the law of compounding growth, and speaking to the actions and motives of a cohort who had not yet done what it took to realize that rate and duration of growth.

They actually are both right.

AOC was not addressing the math at all, nor did she claim that it was mathematically difficult to become a billionaire; just that it was unrealistic to expect that the process of doing so did not select for people with an intrinsic ability to externalize risk and maximize profit in a manner which many other people find distasteful, bordering on criminal if known to the full extent.

And the original post posits that his representative cohort was free from these types of behaviors and thus would remain so.

I find one of those arguments more realistic and actionable than the other even though they both may be true. I'll leave which for another day.