I think it mostly has to do with being prepared for an emergency. When you’re trying to evacuate during an earthquake or a tsunami warning, you definitely don’t want to deal with a parking lot full of cars trying to back out of their spaces.

I suspect the narrowness of roads and parking lots also adds to this, though. I find pulling into parking spaces head first to be so much more difficult in Japan (I still do it from time to time). 🤣