Then the end of slavery in the Empire and and the start of serfdom, more efficient than slavery, after de Diocletian reforms killed the Empire. That's contradictory. And slavery was still a thing after those reforms, as other comments say.
Diocletian reforms, the corruption, civil wars and the inability of defend itself eroded and destroyed all the structures that made the Republic great all those are the reasons that made the Empire fall.
Diocletian reforms, the corruption, civil wars and the inability of defend itself eroded and destroyed all the structures that made the Republic great all those are the reasons that made the Empire fall.