I think Sam does a nice job by explaining:
>There is very little management in the beginning, and that actually works well. When there are fewer than ~20 employees, most companies have everyone report to the founder. That’s optimal in the early stage.
And throughout the article he makes the point to caveat his advice by saying it doesn't apply to small companies. That is really solid and is kind of the difference IMO between advice YC gives and most other startup/business advice.
Where I think (and I believe the OP thinks) that this article could be strengthened is in the beginning by reiterating how important it is to make sure the company has product market fit before addressing any of the advice in the article. YC does a nice job of hammering that in many other posts.
I can visualize some of the founders I know seeing this post and saying to themselves... Great, I'm at 19 people, now I just need to get to 20, then I need to hire HR. When in reality, they don't have full product market fit and should be focusing on that.
My guess is that someone at YC is reading my post here and saying... "All that goes without saying". But, it is such a common mistake that I don't think it goes without saying.
At the end of the day, the article is valuable. I just wish that product/market fit had been hammered as the standard instead of headcount.