Sure, the milk is nutritious but there's not enough from a rabbit to be worth bothering with for a human. And milking rabbits would not be like milking cows. Cows, and even many goat and sheep, stand relatively still to be milked. Rabbits can't and won't and there's no good way to make them.
The theory that wine was discovered by accident is most likely correct because wine grapes contain all the necessary ingredients for wine, including pulp, juice, and seeds that possess all the acids, sugars, tannins, minerals, and vitamins that are found in wine.
Sugar is what the wine yeast ferments to make alcohol. When the fermentation is done the sugar is gone. When there is not enough sugar for the yeast, there will not be enough alcohol in the wine. Certainly in the case of wild grapes sugar will be in short supply and marginally so with some native wine grapes.