Yeah, alcohol is pretty easy to come by, but so are many psychedelic plants and fungi (just pick and eat if you have the right environmental knowledge). Cocoa leaves grow on trees, and while that's not the same as tacocat's crackrock metaphor, South American cultures have been chewing on them and making tea out of them for thousands of years. Marijuana and opium have been cultivated for a very long time too, picking and smoking them doesn't seem much more difficult than fermenting alcohol.
Eh, my point here was kind of that it's so common even animals, who can't wield fire to smoke drugs, can come across it in nature and consume it. As for the psychedelic plants and fungi, I really think you'd be hard put to find any that grow as widely as the significantly broad category of "fruit," but I don't know enough about those species to really say. True about cocoa, I've actually had cocoa tea - but again, clearly, that's limited to a single continent, whereas fruit isn't.
Yeah, and it's not just fruit, but grains can ferment as well. Alcohol can be made pretty much anywhere. Alcohol certainly is one of the prehistoric intoxicants human society learned to consume thousands of years ago, but it is just one of many other naturally occurring drugs. That was my point, but you're totally right, alcohol is very common in nature.