"I don’t think that any professional UX (or UI) designer will question that it takes more than the designer to get the User experience flowing smoothly."
This is exactly why I prefer calling this role Interaction Designer over UX Designer; it's more precise. The Interaction Designer's job includes developing a deep understanding of users and their needs, creating flows, sketching, wireframing, prototyping, gathering feedback, and communicating this information among their colleagues. They are literally designing the interaction between users and a system. They're not designing the entire user experience.