I think this is more age related. I am actually in Japan currently and I can attest that no-one I know will drink daily like in Europe, possibly weekly but the weekly drinks tend to be far stronger and bigger. A European will have a couple of glasses of wine a day and go clubbing every week, Japanese on the other hand tend to only drink occasionally, attend one of the work parties at work with the older guys who don't want to go home - the idea of the older men who don't want to return to annoying homes is common even in Europe
Can public transport be a cause though? I’ve definitely didn’t hold back my drinking as much when traveling somewhere I didn’t have to rely on driving.
In my case, the meals were long and mixed with alcohol. It was like a "tasting menu" type of restaurant, with the booze proof increasing, as the evening wore on.
Lunches are a different matter entirely. They would wolf down their meal in ten minutes. Not a drop of alcohol, until the day was done. Lots of energy drinks; even before the US had them.
I also drink a lot of alcohol with my meals, but I find that often Japanese people who eat with me refrain from ordering alcohol because the next day is a work day - so Fridays will be a day that everyone orders alcohol for example. I have also been in the accompany of plenty of Japanese who get "Asian flush" and a worried about any effect on their health.
In comparison Koreans will nearly always drink alcohol on a daily basis and to a stronger concentration than what Japanese drink - even the Koreans in Japan.