Kotter International is about leading large-scale change, not just managing it.
The vast majority of large scale change efforts fail. Which means that the probability that you have actually experienced a failure, and your people know that and are pessimistic, therefore, about trying something again, is very high.
Managers are trained to make incremental, programmatic improvements. They aren't trained to lead large-scale change.
In the final analysis, change sticks when it becomes the way we do things around here.
Anyone in a large organization who thinks major change is impossible should probably get out.
The rate of change is not going to slow down anytime soon. If anything, competition in most industries will probably speed up even more in the next few decades.