>> He didn’t say that. > Actually he did, or something very close to it.

Yeah, the "something very close to it" is what I quoted. And I'll repeat: distinction matters.

> don't think you are going to get linear speedup by adding more people.

I didn't either say, nor imply, this. Of course communication and coordination is overhead. Let's quote Brooks from the same article some more: The maximum number of men depends upon the number of independent subtasks.

Which is why in modern times you have a bunch of theoretical and practical research around team topologies, DORA, Reverse Conway Manoeuvre, the push to microservices, etc, etc. You can boil all that down to "maximize team independence while making each team as productive as possible."

This is a wonderful tangent (and if this interests you, I heartily recommend the Team Topologies book), but can we just keep in mind the gp never actually said he was overhiring for a single project? Parent latched onto a wrong idea and ran with it.