You are forgetting what people did before psych meds were available. Almost everyone treated themselves with alcohol and tobacco. Coffee is up there, too. There is cognitive adaptation, not denying it, but only up to a point.
People were constantly bombarded with death, disease, things like starvation were near term risks, violence was everywhere, etc.
You're also overestimating the prevalence of alcoholism. Alcohol consumption was largely driven by safety and necessity, not abuse. Alcoholism was arguably more of a social stigma historically than it was today, certainly with harsher criminal penalties in many societies.