How possible would it be for the title of Roman Emperor to die in the West after the title fell into disuse before Otto was crowned by the Pope?
Simple. Prevent Charlemagne from unifying Francia and getting crowned Western Roman Emperor in 800
......After it fell into disuse before Otto I.
It's been more than a century after Charlemagne at this point. The POD is the gap between Berengar I and the crowning of Otto I.