The reasons why the Akkand Empire doesn’t last for long .
There were rebellions from the conquered city.
2) There were some serious problems about food supply, the main food supply area suddenly rained less and food was lacked in the north area.
3) Trade relationship resisted.
Disagree. Those three theories cannot hold up this phenomenon.
1) The conquered city was too weak to fight against the Akkand Empire.
2) There were agricultural technologies like irrigation that can bring water from remote areas and store the rain water, so the food chain will not be broken.
3) The Akkand Empire was always developing new trade relationships which can provide kinds of resources and make up the losses.
Some people prefer to buy new technological devices immediately when they become available. Others prefer to wait until many people have adopted them. Which way do you prefer?