So, since I'm big into the Roman Empire...does the downfall sound similar to you?
Corruption in the government during its collapse, was a HUGE problem. They gave themselves a lot of benefits, controlled what information was heard amongst the population and took a lot of bribes. Amongst other corruption problems.
They brought in cheap labor en masse (Gauls, and not slaves (though Romans did use slaves), but the Gauls got paid and became full citizens)...who later rebelled and took over a large portion of the empire. Even the Roman's own army, consisted mostly of Gauls, other barbarians and mercenaries...the army turned against the Roman empire as well. More than half the Roman population wasn't even truly Roman.
The population was lazy and relied on the Roman government for almost everything. They got free hand outs and many free benefits, leading to the bankruptcy of Rome (among other things)...which played a part in the rebellion of the Gauls.
A variety of events led to the downfall of the Roman Empire, but those are the top things I can think of. There were some other events that led to the collapse, but those were the main things: Corruption, laziness, Gaul rebellion.
All that is 100% accurate of the last era of the Roman Empire. I studied the Roman era quite a lot, some through Wiki, but mostly through reading books on the history of the Roman Empire that I found at a couple libraries and bookstores.
Again. Sound familiar?