In its final decades, the Western Roman Empire was in crisis in numerous ways. The cities were in decadence, aninthe commerce with it, meanwhile the rural population was increasing and the lack of slaves combined with the barbarian invasions, made this people work for the protection of their lords. Also, the so called barbarian tribes were not only the pricipal invaders, but the main source of protection of the WRE as the roman military was declining, and became very influential in the roman politics.
In resume, the bases osf feudalism were here.
So, i was thinking about a possibility : if, instead of being politically replaced by the barbarian kingdoms, the WRE had continued its existence, but leaving all the barnarians to settle in the regiona of the empire, offering lands and total autonomy in exchange for nominal subordination, being their territories still considered part of the Roman Empire? So we would have the WRE becoming a more roman and non electoral version of the Holy Roman Empire: a fractured "state", with little central authority, but "surviving" in the middle ages with its old borders almost intact in paper.
Could this happen?
Consequences ?
How long could this last?