I've worked with a number of product managers who've grossly overestimated their competence in these areas, and who've been mocked and ignored as much as possible by the development team as a result. I'm familiar with a large, well known software company that uses such a job description. I worked with a product manager who left that company for mine. He was awful. He never gave customer-focused requirements. Instead he'd define implementations as if he knew what he was talking about, and I'd have to play 20 questions to figure out what problems he was trying to solve.
The best product managers I've worked with have leveraged their strengths and trusted others on their team to do what they're best at. In my experience, these product managers have always had a very strong customer/user focus. My favorite product manager was at a medical imaging company. He had been a tech before he moved into product management, so he knew deeply what our users needed from our product, he had many connections in the user community, and he knew how to listen. We'd challenge and ask questions, but at the end of the day we deferred to him in his area of expertise, just as he challenged and asked questions but deferred to us in our area of expertise.