Is it a surprise that drugs induce chemical changes that affect perception, sometimes permanently? I've always wondered what is it isn't that it shows you somet

Is it a surprise that drugs induce chemical changes that affect perception, sometimes permanently? I've always wondered what is it isn't that it shows you something that makes people almost universally come to the same conclusions about reality.. what if it just flips a switch? The similarity in thought I see among different users of psychedelics is just so big. Why should it be a surprise that it's chemical? Opiates can flip a switch in your brain that makes you way more habituated than a natural stimulus with the same level of pleasure(ie heroin users will say they don't like it any more they like spending time with their kids, but still will neglect their kids to do heroin because they can't say no). Marijuana can trigger latent psychological issues in those who are at risk. Maybe psychedelics pushes some switch that makes people think differently, even if they're aware of it and trying to convince themselves otherwise?