Character change is one of the best ways to construct a dynamic story, but it's not the only way.
Another way to drive a character to act is to threaten the character's self-definition. Sometimes the character's self-definition extends to a world-definition. For example, a dragon's self-definition could be I am powerful and I eat people. Viewing his world through the lense of this self-definition, he might say Power makes right. Therefore, dragons rule the world and have a right to eat people.
If all you do is describe dragons going around flexing their muscles and eating people, you have no story. But throw in a force opposing the dragons and threatening their supremacy. Now the dragons must either defeat the opposing force, preserving their self-definition, or, failing that, they must adapt to the new circumstances. If they do adapt, they will change their self-definitions, which is, voila, character change. Change does tend to sneak in there.
If they don't adapt and don't change their self-definition, they eventually destroy themselves, perhaps physically, certainly spiritually.
Failure to change in the face of circumstances is the hallmark of tragedy, high and low.
