A main reason for that fall of the Western Roman Empire was that the people did not have many rights. The government had mostly all of the control in Rome. Most of the normal citizens would just be farmers, and couldn't be in the government.
A main problem was that Rome had economic problems. No one in the city wanted to be in the army, because they wanted to be religious, and they just wanted peace, and there weren't as many kids to join the army. This lead to the Roman Empire hiring Mercenaries. They were Germans that went to war for little pay. There were too many slaves in the city. farmers quit their jobs, because of the high taxes. They quit their jobs, because slaves would do it for free. The city couldn't get all the supplies they needed with all of the slaves doing the work.
The loss of money, and people being poor also lead to the fall of the Empire. When the empire stopped expanding, they couldn't get that much money for the empire. The government had to put a lot of money into the empire, to maintain the safety of the city. A lot of people left there jobs, because of taxes. People just couldn't afford it anymore. The establishment of the system welfare made people not want to work. They would still get paid even if they just sat at home all day. Then there were no jobs, which lead Rome into having no money.
A big part of the fall, was the Barbarian invasion. Six different tribes attacked Rome which destroyed most of Rome. It wasn't a unified invasion, because the tribes all came from different directions.
A lot of things lead to the fall of the Western Roman Empire. There wasn't just one problem that lead to the whole