How could such a powerful empire collapse?

The more power the empire inherits, they often become blind sighted when it comes to making the right decisions. The higher up in the ranks, the more privilege you receive, the lower in the ranks you are, you often receive neglect. The oblivious leaders are eventually overthrown by their people, or often times citizens created fights among each other.

i’m   sure probably just geuss and see which one you can get right, i’m pretty sure it is the combination of goods and services