It's not unpopular, it's just old.
Keep seeing "Why is X anime not talked about/unpopular?" when talking about older anime.
Maybe it's just an issue with new members of the community. But as an older fan, while I'm glad they get attention still, it's annoys me for some reason.
Sure they are not popular now, but they were. And it's ok. We have a lot more to watch compared to the past and it's easier to access legitimately.
But if it's a pre-streaming era anime, please don't call it unpopular. It most likely was in it's time.
But by all means keep talking about older shows and sharing them.