lets not forget, back in the day the drink of the house was wine, not apple or orange juice.
things changed alot since production commercialized
Before refrigeration, I don't think juices were a very viable long term option. I think it needed some vinegar or alcohol to prevent it from spoiling (hence apple juice being fermented into apple cider). Wine has an inherent advantage over water that the alcohol should prevent it from going rancid and pathogens growing in it. The availability probably depended on the region and whether grapes were easily accessible. In many areas of Europe, iinm, the standard "wine" was raisins soaked for a few days (probably being as raisins were the most efficient non spoiling transportable form of grapes). I'm assuming it wasn't very good wine. Most alcohol probably came from fermenting grains or potatoes that they did have easier access to into basic mashes.
A person probably developes a tolerance pretty quickly if their average drink is mildly alcoholic, and doesn't get tipsy or inebriated from it. Idk if it's good for your liver long term if you drink too much for it to synthesize and regenerate, but I also don't know if that was their primary longevity threat.