It's difficult to explain the cause. You can't really account for it by a simple tipping/no tipping divide. In other countries that don't do tipping, you'll end up wishing they did because the service is so abysmal. You can't get decent service or expect a good waiter or waitress, because nobody is motivated to do the job well.
I've been to Japan many times. Tokyo, Kyoto, Nagoya. Japanese culture is exceptional in many ways—you can't pretend that their culture is normative when applied to the west. My point still stands. You can't pay service staff minimum wage or slave wages and expect good service. This is why the tipping system developed.
Ah, that's bullshit. I've been all over the world and I'm guessing by your comment I'm more travelled than you. Currently, I'm in the Philippines, where there's no tipping. Go ahead, come down here on a trip and see what happens. No tipping. And the service is abysmal because nobody has any incentive to be an excellent waiter or waitress.
What you don't understand is that tipping became a thing in order to reward good service and provide a decent income to service workers. It's not perfect, but it's there for a reason.
I just finished saying that I've been all over Japan. And you missed where I said that Japanese culture is in many ways exceptional and not like other cultures. It's not like the rest of SE Asia, for instance, where there's no tipping and you have to wait for a half hour to get your cheque.