I live and work in Japan, but I'm still in this picture and I hate it... Though my work-life balance has progressively gotten better. I don't, however, let my subordinates do that; I want them to have real time off. If they answer a slack or something, it's helpful, but I'd rather they didn't think about work in their off time. I try to be the leader I wished for.
I still think of work in Japan as endless hours spent at your desk, waiting for your boss to leave so you can leave a bit after, with little recognition and complete loyalty (or at least feigned loyalty) to your bosses and the company as a whole. Is it still the case today?
Some companies are still like that. Moreover, some people are just like that... and that's the crux of the issue. Social pressure is huge in Japan, so it's hard for people who want no part in that to stop when others keep doing it (even if no one orders or even expects them to).