A Product Manager’s Job
Josh Elman

Nice article. Engineers or designers who build a product in the field tend not to be able to care about checking whether the product meets users’ needs.
But it’s not an engineers’ or designers’ fault. In fact, they also think in their hearts that the product they are working on right now might not meet users’ needs. If possible they wanna remake it from nothing! Of course, they cannot say such a thing because they are the very persons who did that. As a result of that, the team or company ship a bad product nobody will use (or cannot even ship eventually).
So I believe that a person in charge of assuring the quality of the product to meet users’ needs and people who actually make the product in the field should be completely separated intentionally. Product Manager is the position who play the former role.