Main role of the PM is to prioritize: what get build/shipped first, what later, what not? To do this a PM has to balance and understand the needs of the custom

Main role of the PM is to prioritize: what get build/shipped first, what later, what not? To do this a PM has to balance and understand the needs of the customers, the potential customers, the direction of the company, the direction of the market, the capabilities of the competition. The engineering details are better left to the software engineers, architects, key users and UXers.