In so many projects, this is the cause of delay, rework, and confusion. Instead of looping in folks from all aspects of the team early on, some mix of disciplines will work in isolation for months, and only when they are fully committed to the direction they’ve decided on, will the full team be engaged. The excuse is often to save precious dev time, but it means that the best time for feedback has passed. From my point of view, it is often the dev team that is left out of the loop until it is time to execute (with no time for course correction), but the same thing can happen with any set of people. Engineering could decide to rework an implementation, without critical knowledge of an additional use case, or a ‘soon to be announced’ strategy change. In larger teams, you can’t bring everyone together around an early-stage idea, but representation from key groups will prevent a lot of back tracking later on.