Why a Japanese series from over 10 years ago, despite having a strong plot, didn’t become popular?

Just came across this in one of the recommendations 🤔 Japan really knows how to pull off this kind of series. I’m wondering why this wasn’t more popular back then, even though the plot is definitely up there.

It came out more than 10 years ago, but with shows like Alice in Borderland gaining traction, I’m curious—why didn’t this one blow up the same way? Was it just ahead of its time, or did it miss something that could’ve made it bigger?