Consider that the fact that there’s a tv show about it means it’s a novelty in Japan as well.
It’s great that Japan has a civil society that makes a show like that possible, but don’t mistake it for more than it is. It’s the same mistake as generalizing from what you read in the news: it’s news because it’s unusual.
No, it really is commonplace in Japan. It makes good TV because little kids are cute as heck. Not everybody has kids, and even if you do, they don't remain five years old forever. So even mundane stories about little kids can stay popular.
It’s great that Japan has a civil society that makes a show like that possible, but don’t mistake it for more than it is. It’s the same mistake as generalizing from what you read in the news: it’s news because it’s unusual.