In academic literature, "ur-" doesn't just mean original, as much as it means "essential essence of" or "fundamental". In contexts where you're talking about the first/original thing, or something that provided characteristics that would eventually become a trend, "proto-" would be more appropriate.

For a famous example, Umberto Eco's essay "The Ur-Fascist" isn't describing what the first or original fascist movement was, but instead exploring what makes Fascism Fascism. This usage seems to be pretty consistent across academia, who engage in the vast majority of cases of slapping foreign prefixes onto English words.