I know a couple of people outside of my field who are taking stimulants and talking about it. I know a couple people within my field (and outside) who take drugs solely recreationally, not as a performance booster or a way to get to sleep or anything, and certainly not on a regular let alone daily basis.
And I definitely know enough people within my field closely to know that they're not taking stimulants.
I think you just inhabit a different world, yes. (And I worry whether you inhabit a world of people who think they're productive; a sizable number of the the really productive and skilled people I know tend to be so clean that they don't even drink.)
I think we all inhabit a world of people who think they are productive - in the sense that many people optimise for the appearance of productivity as opposed to optimising for actual productivity or value generation. I can honestly say that stimulants make a vast, objective difference to my work output and quality (but I actually do have ADD so I'm not a good measure). I have also seen many other people produce extraordinarily good work on stimulants. At the same time some of the very best people I know don't need them and wouldn't touch them. We don't all have the natural ability or background those people have, so stimulants are a proxy. Quite probably many people are not achieving their maximum potential simply by using stimulants. Quite probably many people are decreasing the quantity or quality of their output by using stimulants. But objectively (as in, see the scientific literature) they do work. Whether people make them work for them is a different matter.
What objective measures are you using to evaluate yourself? are you in the top 1% of earners for your experience level, position, city?
Yeah, I guess so. I'm also in Berlin, and a lot of people take some kind of stimulant. As someone not taking any stimulants (not even coffee), it was quite hard to spot it in the beginning. At one point I was working with a larger group of people and only after a few months I was told that more than half of them were on some kind of stimulant almost constantly.
The closest I came was when I had some papers on my desk that were given out for free somewhere and somebody informed me that that was used mainly for smoking pot. I had no idea.