You might not need a dedicated product manager at all companies, but someone needs to embrace and act as it. In some situations I have gladly taken that role, in other not.
I would say this more aggressively, product manager shouldn't be a specific role at any company. Someone needs to do that work, but making a product manager role, who can be unable to do any of the actual tasks to make the product function, is a bad idea. It's just encouraging people to play politics, and discouraging people from playing politics is one of the most important things for any org.