When an object is flexible and adapts easily to the changes in its environment then it is more likely to survive those changes.

On the other hand when it is rigid the same changes will permeate the inflexible structure and force it to change, often in ways that will cause it to shatter or disintegrate.

A simple example: note what happens to a glass sphere when dropped vs. the same for a rubber sphere. The "flexibility" or "adaptability" of the latter to such an environmental change is significantly greater. On the other hand, glass is more "adaptable