[tptacek]

Think about the roles of a PMM --- customer discovery, pricing/segmentation, roadmap.

In a single-product startup, which is what most startups are, the whole company is doing these jobs. Product/market fit might not be established, or might be just months old, so the people doing sales are also doing customer discovery. The management team is agonizing over pricing and isn't ready to delegate it. The CEO might be reading every commit, and the roadmap is obvious.

I was a PMM for a couple years, and the role was described by a friend to me as "president of the product". In an organization with multiple products, you can need that role; one person keeping track of every business facet of every product doesn't scale. But you don't delegate roles until you need to. Like Jason Fried recommends (paraphrasing): hire when you've gotten so good at a role that you're tired and can't keep up with it anymore.