Caffeine is pretty well studied and it's known that the long term health effects are nothing close to cocaine. I doubt if there was any good science back then on the long term effects of cocaine, let alone enough education for the populace to know and understand it.

However social perceptions may change anyway. What we consider as not serious may be considered much more serious in the future. For example many people get headaches or even migraines as a withdrawal symptom of caffeine, and we don't consider a headache to be serious.

But I saw a Star Trek episode once where Picard gets a headache and it was a big deal because those had been solved for hundreds of years by that time! Turns out the ferengi were controlling his mind or something. So caffeine may be considered a serious drug in the future if it interferes with the detection of alien mind control devices.