In my experience, 90% of product managers are no good at their jobs. They fall prey to common mistakes that prevent them from effectively leading, and thus fulfilling their true responsibility, which is making their product successful in the market. Period.
People often conflate "intuitive" with "simple". In the world of software product design, making something intuitive can be quite complex, and requires a solid understanding of cognitive biases and other traits.
Product Management and Product Marketing are two different, but partially overlapping functions. Product Management optimizes the product based on the market, and Product Marketing optimizes the market based on the product. Working together properly, they can deliver incredible results.