Lucian was an Assyrian of Greek culture who wrote exclusively in Latin
What we do know of the collapse of the Roman empire is that it was due to two economic reasons:
1. the united Roman Empire was a slave-based economy. This meant giant latifunda - farms, run by slaves, enriching wealthy men who only got wealthier while poorer folk had fewer to no opportunities to rise. Also a slave-based economy depends on constantly getting more slaves. When that stops, the economy collapses.
The eastern Roman empire successfully transitioned away from slavery, but that took time.
2. inflation and debasement of currency - when currency could not be trusted, that eroded trust in the institutions of Empire.