As other commenters noted — Rome did almost fall apart and come back a few times. Peter Brown has a bit about how the crisis of the 3rd century was reversible b

As other commenters noted — Rome did almost fall apart and come back a few times. Peter Brown has a bit about how the crisis of the 3rd century was reversible because it was fundamentally about control of the empire, rather than disassembling it. My headcanon is that while the elites of the empire found more value in controlling the reins of power rather than carving out their own fief — that's what prevented collapse.