alt Hacker News> Coffee is a universally available, productivity enhancing commodity
The analogy carries further than you intended. If you have never reached addiction stage, then there is no factual productivity enhancement. "But I'm so much less productive if I haven't had my morning coffee" Yeah, because you have an addiction. It sounds worse than it is, if you just don't drink coffee for a few days the headaches will subside. But it doesn't actually enhance productivity beyond placebo.
I'm not so sure. The stimulation can also self-medicate for people with attention issues. I've tried quitting coffee before for weeks and I get so spacey it is difficult to work on major projects. I try coffee again and suddenly I feel quite capable. Perhaps I didn't quit long enough, but at this point after multiple attempts quitting with similar results, I've just accepted it.