This article hits the nail on the head. Large teams need coordination, and coordination is a job that both takes up significant time and operates in a very different manner from engineering work. Without having a few people specialize to do this work, you are forcing everyone else to compromise their engineering capacity to make up the difference.

The real difficulty, which the author only touches on at the end, is optimizing the number of managers. Not only are there diminishing returns to adding excessive managers, more management creates more workload for everyone past a point. But even though the organization would benefit from scaling back the number of managers, there is an obvious individual disincentive to say "it would be better for you all if I was fired." Thus once you get too much management, it tends to stick around[0], and therefore it is critical to avoid excessive management in the first place. The article articulates clearly why you need more than 0 managers, but it should include strategies for determining whether you need an n+1th manager.

[0] There is one fix. It's tough to get rid of excess management, but an organization can potentially grow into an appropriate size for the amount of management it has. This may be a challenge for a mature company, but for a startup like the one featured in the article hiring too many managers is just hiring an appropriate number of managers early.