I suppose I should have waited for someone so that I could take an action shot, but to be honest you only occasionally see somebody filling a jerrican here. The 10L boxes of red cost about 20€, so 2 €/L, and the pumped stuff is, I think, 1,80 €/L and less drinkable.
This is the wine co-operative hereabouts https://www.vignerons-des-alberes.com/ . I went there yesterday to restock after Christmas and bought 12 bottles of Prestige rouge at 6,80€/bottle, so about 9 €/L. We decided long ago that life was too short to be drinking cheap wine.
I read that in the 1950's the recommended limit for wine in France was 'not more than a liter/day'. These days the recommendation is 'not more than 2 glasses/day, and not every day'. We mostly stick to that, it's just that we have very large glasses !
This site (in French) says that the average alcohol consumption in France was 200 L/year in 1960 and had fallen to 80 L/year in 2018. Amongst other things, it says wine was served in school canteens in the 1950's ! In 1956, the state banned the serving of alcohol in school canteens, but only for those under 14 !