Oh yeah, all sorts of contributing factors that interacted. It's fascinating to study, and also to see how remnants of the Western Roman Empire hung on - the entire Aurthurian legend is nothing more nor less than a struggle by the old Roman-British allied with the Celtic tribes against the Anglo-Saxon invasion. And then you have the invading tribes who wanted nothing more than to become Roman - adopting a veneer but notthing more....i went on for centuries, a fall in slow motion into the Dark Ages - meanwhile the old Roman elite was fighting between themselves and in the end all that was left of Rome was Byzantium.....which hung on until 1453.....
I would submit that gross social inequality, individuals’ rights, wealth disparity, gross exploitation of satellite territories’ resources (human & natural), lavish excess among the top “1%” (or less), increasing authoritarianism, etc, etc, we’re KEY factors…
Sound familiar???
We. Told. Them. So.