Major change is usually impossible unless most people are willing to help, often to the point of making short-term sacrifices. But people will not make sacrifices, even if they are unsatisfied with the status quo, unless they think the potential benefits of change are attractive.
Most leaders underestimate how difficult it is to move people out of their comfort zones, and how new ideas can be talked to death by skilled filibusterers. A common attitude is, "Well, we have our problems, but they aren't all that bad, and we're mostly OK."
John Kotter, Leading Change