Can the product owner become the customer as well?
Many times the product owner is coming from the funding organization, so they are a customer. But keep in mind that they’re part of the scrum team themselves, so they’re not at some higher level as you would traditionally handle a customer. They’re going to have to balance a lot of differing agendas, many times conflicting agendas from the business itself. So, the best case scenario is a product owner is as objective as possible, most likely coming from the funding organization, being able to balance the different conflicts between all the different business units, and driven by the value of the business idea itself.