I think alcohol on flights started when commercial flying started. It was a great social experience with folks dressing up in their Sunday go to meeting clothes and enjoying a cocktail on the flight that endured into the 70's.I have never understood why alcohol was a thing on planes in the first place, but I'm also not much of a drinker myself. Consider the circumstances: narrow tube 30k feet off the ground, no room to walk around, limited bathrooms.
I get that it is a way for the airlines to make money, but frankly they'd profit greater if they just charged for selling sodas.
Are people so substance-dependent that not being able to drink during a 2 hour flight is a major a problem?
Typically on short flights, a can of tomato juice or water is all I get, but on the long overseas flights, a cocktail or two helps put me to sleep. Usually a couple of hours into international flights, some idiot that was toasted before getting on the plane gets rowdy and the bar gets closed anyway.