Oddly enough, Japanese people do it because it's not that much trouble and the rewards for the overall community are substantial—perhaps even existential—in nature. I agree with you that a selfish, lazy culture where everyone is in it for their own short-term gain will not be able to function in this way. There is indeed a problem with foreign enclaves in some Japanese cities refusing to put in the effort. As far as I know, that is where the municipal authorities come into the picture, levying fines, etc.
There is a very strong "can't do" attitude that is pervasive all across America and Europe (with perhaps Scandinavia excepted) and it is quite obvious once you join a group that actually puts in the effort to serve the group's overall interests based on rational thinking.