>>283660695 (OP)
It's because Lucky Star, unlike Haruhi, offers an experience that, to this day, is almost wholly unique to itself. Haruhi, aside from being 2000s-styled and KyoAnimated, is truthfully nothing but a school drama with a charismatic hot girl and a supernatural twist. We've seen dozens of those emerge within the subsequent decade. But Lucky Star is something genuinely revolutionary: A chibi-styled candy-colored fluff show that revolves around a cute and relatable comedy duo consisting of a Dionysian tomweeb and an Apollonian tsundere, and KyoAni made sure to give it most powerful design, directing, art, animation, music, voice-acting, etc, that it could at the time. Haruhi may be a classic of sorts, but Lucky Star is the moe equivalent of crack.