His core premise is that one's not required to cheat, use immoral loopholes or abuse anyone to become filthy rich, as a prominent US politician has claimed. That stands unchallenged.
His core premise is terrible if not outright facetious given the case he made. That the girl who is going to become a billionaire in his example has a startup that makes a product that everyone loves does nothing to disprove the point. Billions of people love VLC media player but Jean-Baptiste Kempf didn't become a billionaire.
The difference isn't the product, it's that what makes the startup founder a billionaire is that they're willing to pawn off their invention to people who do all the unethical things, while they laugh on their way to the bank, that's the point of the big check.
In some sense I prefer the robber Barron over the startup founder because at least the former doesn't pretend they're a saint between they've put one level of indirection between themselves and the exploitation.
One can't be held responsible for unethical things done by his creation once it's sold.
In a free market everybody can choose to sell or not, who to sell to and under which terms. Therefore, he should be held morally responsible for giving away control of his creation to the wrong people, or for not ensuring his creation can't be turned into something bad.
Then again, they don't get rich by cheating, abusing or whatever, they build a legal thing and sell it. You wouldn't go after a knife maker if someone used his knife to stab someone.
If you make a successful crowdsourced reviews website by building trust over time with contributors and users, and by any mechanism it ends up getting owned by an advertisement company that makes a business out of making it pay-to-win, should you not be held responsible?
I'm not talking about legal responsibility here, just moral responsibility. Ideally the former should follow the latter but it's not always the case.
Even then, has say Databricks or Canva been guilty of unethical conduct?