The two most popular Agile frameworks today suggest a preset starting method. Scrum with cross-functional teams and SAFe with Essential SAFe.
Both have the rationale that people need to start in a well-defined way and abide by it until they learn more. SAFe also promotes that consistency of practices is needed across the organization.
Both assumptions are flawed. While people do need to have a well-defined start, there is no reason not to provide them with something that works best for them. Those who believe in empiricism as the main guide, however, will think this not possible. But that just suggests that a Flow and Lean approach would be better.
Another challenge with a set start approach is that it avoids teaching people to learn how to change their process. The fact that they make bad changes is more indicative of the framework’s lack of guidance than it is that people need to be locked into it.
Consistency of practices across an organization is the anti-thesis of Agile, Lean & Flow. While we want consistency of objectives, different teams will need to self-organize within the bigger picture.
Starting from the bottom will neither create this nor guide us in how to.