Why is Galactic Civilization usually the forgotten one of the bunch?

Whenever there's discussions of Space 4X games we all know the most talked ones.

It's usually Stellaris and Endless Space 2 dominating discussions followed by a sort of equal mix of Distant Worlds 2/Sword of the Star/MOO2

But wasn't Galactic Civilization one of the big one's of the genre? I know GC2 was well beloved, since it keeps being heralded by the community as one of the best 4x's, so what happened to the series it lost so much mindshare after that.