Feudalism and monarchy are awful and oppressive, but both are still better than being raided.
The Roman republic became too large for an effective administration, which led to a lot of power staying in the hands of the few, and had a lot of flaws and blindspots. But despite that, it was still a way better system than what came next.
As for Romans, they, and most of Mediterranean experienced objectively best living conditions in all of humanity until modern times during 1st and 2nd centuries. Which is exactly the principate period.
Edit:
My point is not that monarchies or empires are better. It is that they are more effective for that technological level.