Southeast Asia is heavy on bikes, and used to be more so than now, and they didn't have infrastructure or culture --it was need. Japan is heavy into bikes too, and there aren't dedicated lanes, not that I'd object, but it's not necessary to make it popular. The one thing in Japan, where accidents aren't as regular as in southeast Asia, is that both bikes and cars obey traffic signals --I think that helps a lot. Also…
Right, in Japan you don't need dedicated lanes quite as much because of the narrowness of the streets, plus it being accepted to bike on the sidewalk when there's room. And of course density being high in Japan helps.
When I walk on the sidewalk in Tokyo i'm always waiting to be clipped by a bicycle because I changed direction too quickly. You see people riding bikes through shoulder to shoulder crowds.