I'm not really sure what you are arguing. Of course if its a one man job (or a couple) and the .. product or whatever isn't system/safety critical even having a PM is probably overkill and the overhead of "any" process likely just wrecks the output.

But if you need to organize 50+ engineers and actually produce a ... product? That people/agencies/customers expect things of you sure as shit is going to need a definable goal, verifiable output and a somewhat chronological way of achieveing that. Waterfall it is (with reasonable iterations).