Well yeah 40k ripped off a ton (and I mean a TON) of stuff, but it managed to give it its own flavor and "lore" over the decades to the point that it really is its own animal even if you can see the lineage of a lot of its ideas. Like I daresay the depth and breadth of lore, art, and backstory can give any other fictional setting a run for its money. Lord of the Rings, Star Wars, Star Trek, you name it. There is just a mind-boggling amount of material about literally every faction in 40k that stretches as far as the eye can see.
Starcraft managed to become its own thing over time, but when it was in development it literally started as a 40k game (just as Warcraft was a Warhammer game) and then the licensing deal fell through, so it turned into a 40k game with the serial numbers filed off.
Like don't get me wrong, I played the absolute shit out of Starcraft and Brood War and read the same original trilogy of novels and enjoyed them thoroughly, and someday I'll get off my ass and actually play Starcraft II and probably have a good time with it, and I was gutted when Starcraft: Ghost got canned (and I still burn a candle for Nova and was thrilled when she got some time in the spotlight in Heroes of the Storm and got her own action figure and everything).
But Zerg are totally (inferior) Tyranids.
