@Zeke Phantasy Star isn't that popular, in Japan it is huge, but outside of Japan it has always been pretty niche. PSO2 and NGS in Japan on it's own has 10 servers, the rest of the world only has 4 servers, and two of those servers had a much lower player count than the other servers after only 1 day. Phantasy Star is still very niche outside of Japan.
Another good indicator of popularity these days is how well the game does on social media and streaming sites. People on social media aren't talking about Phantasy Star and there aren't any notable streamers regularly playing the games on Twitch with high numbers from what I can see.
There is also the media and how people interact with news on Phantasy Star games. The build up to NGS has been almost non existent. The only place I have seen consistent news of NGS was from a site call Twinfinite, but if you look at the replies to the articles on NGS, it's almost non existent. Every now and then, the big sites like IGN and Gamespot will announce something, but again, nobody interacts with the article. I haven't even seen anything on IGN about the release of NGS.