agile user stories: objection #2

Product owners represent the users. This is a central premise of the agile approach. Probably a wise one as developers would not want to own the user and would need guidance by the people who run / own the solution that users would use / purchase, etc. passing on, or probably sharing the responsibility of knowing the users makes sense. However, more often than not, product owners are not in a position to understand the users. They may have marketing segmentations, sales stats, feedback forms, anecdotal evidence, personal experiences but all this information relates to exhibited behaviour not insights to users needs and goals that can only effectively be identified by qualitative user research. Only then would the product owner and developers be able to fully understand the user and stat building user stories.