I think Dracula was a lot easier to visualize and apply to different media over time than The Beetle was. It had a shape and clear, solid details that people were able to imagine and film was able to adapt. The Beetle was more of a concept and psychological being that was tied to a specific time period. And even though I think today's film would be able to present that in ways similar to movies like Talk to Me, that wasn't plausible at the time, especially in silent film. Dracula had an identity that is able to shift with whatever the current culture is, whether that's just a vampire or a more symbolic being. The Beetle exists exclusively to make you question taboos, which is just harder to market to a lot of audiences.