The most accurate evaluation of the impact of feudalism after the fall of Western Rome is:
Feudalism was an effective protective measure against Germanic tribes.
Feudalism emerged as a social and economic system in response to the instability and invasions that characterized the period following the fall of the Western Roman Empire. It provided a way for local lords to offer protection to vassals and serfs in exchange for service and labor, helping to create a sense of security in a chaotic environment.