There are two very different strategies in adopting Agile in a large organisation, horizontal or vertical. In other words, you may take one product first with narrow and deep focus. Or you may focus on the vertical coordination layer, which is often perceived as The Scaling Problem.
You may forget the laws of internal marketing, but they will not forget you. Lessons from Moore's Chasm and Strategic Selling.
The three natural stakeholders have common and conflicting interests. This creates three different subcultures, causing a leadership vacuum in the middle, where product decisions need to be made.