Final answer:
Dynastic decline in the three major empires resulted in the rise of new dynasties and was a gradual process, rather than leading to the collapse of all three empires.
Step-by-step explanation:
During the decline of the three major empires, several things were true. Firstly, dynastic decline did not lead to the collapse of all three empires. Instead, it resulted in the rise of new dynasties. Secondly, while external invasions played a role in the decline of some empires, they were not the sole cause. The decline was a gradual process that involved a combination of internal and external factors. For example, in the case of the Roman Empire, immoderate greatness, conquest, and the loss of support contributed to its decline.