Dude what the fuck are you talking about? The Roman Empire was whittled away by barbarian attacks over the course of a century before ultimately being completely overthrown by Germanic barbarians. In the fifth century, not the 20th. The Roman Empire “moved north”? What the fuck does that even mean? You think they said “Hey, our empire is so completely successful, let’s completely abandon our entire civilization and move somewhere else!” No, you fucking dumbass. The empire collapsed because they began to embrace femininity and degeneracy as a culture and were gradually rundown by cultures that embraced masculinity and self-control. The fact that we utilize some of the successful aspects of roman society does not mean that the Roman Empire never collapsed.