The only thing that stood out was that the argument the author set out to dispel had a much simpler flaw. In the original argument, point number 3 (having less skin in the game leads to bad decisions) is the weakest one.
That statement isn’t really a first principles fact, but at best a hypothesis. IMO, not even a good one. For all we know, having less extreme exposure may lead to better decisions, as the founder may be open to more calculated risks. And even IF true that statement doesn’t address the tradeoffs: maybe bad decisions are outweighed by the ability to outrun the competitors due to influx of extra cash.
While there is certainly some correlation in such arguments, the bar for proving causation needs to be much higher than a pithy statement.
All that being said, I really enjoyed the rest of the argument.