End-users are on the project team. The system has to do what operations managers need, not what technologists think they need. The team is sequestered. Freed from regular duties, team members work in a separate project room where they can kick around ideas without distractions from regular bosses and colleagues. The team can make final decisions, but on short deadlines.
Implementation is gradual.
Madness lies in trying to roll out a system simultaneously to every plant in 20 countries. Taken one country or business unit at a time, it becomes manageable. Ample time is spent on training. Old security blankets are discarded. Companies may be tempted, for example, to force the system to keep generating paper reports just because the staff is used to them.