wouldn't it be more accurate to say its their star trek? admittedly not a gundam fan but I don't see it talked about or merchandised nearly as often as evangelion.
Maybe not in Western countries, but Gundam is HUGE in Japan and neighboring countries like Taiwan. A big part of it is that the merchandise is heavily focused on model kits, like Warhammer on steroids.
Oh yeah, I forgot about gunpla. I think the reason I'm so unfamiliar with that side of the mecha world is that it's so fractured if that makes sense. I have friends into it that I could ask but I don't need another expensive hobby haha