So it makes perfect sense that contemporary AAA devs would have no idea it even existed.
I guess I'm mostly just amused by the initial comment suggesting Halo 3 of all games as a super incredible cultural impact game. I just can't see it like that at all -- at the time it was just a capstone to what Halo 1 and 2 set up. And in modern times, Halo is so irrelevant that it's probably going to be on Sony's console.
https://www.youtube.com/watch?v=reaXYMihM1Y
https://en.m.wikipedia.org/wiki/Marketing_of_Halo_3
Halo 3 broke sales records at a time where you needed to buy physical copies.
It had a famous Superbowl ad https://www.youtube.com/watch?v=GKDkKKt9Y7I
Perhaps I'm just missing your argument. Is your argument mostly about the immediate "pop" surrounding the launch, rather than any sort of longer term cultural impact? If so, then sure, I'll grant Halo 3 had one of and perhaps even the largest launch hype of all time from the physical release age. Still it's not like Halo 2 wasn't hugely popular at its launch too, though 3 was probably bigger. And of course the already mentioned Modern Warfare had a big launch, though by MW2 the whole culture of launch hype with midnight releases and camping out and so on was just about dead thanks to digital distribution and such. You had other games later on with crazy marketing too -- how are super bowl ads relevant? Dante's Inferno (2010) is a game I've never played but it also had a super bowl ad I've never seen until now. I'd dare say its impact is far less than Halo's, both at its launch (seems to be a God of War clone) and since.
But if you really are arguing that nothing has had a bigger long-term cultural impact since, the single counterexample of Minecraft is enough to stand against that. Speaking of God of War, there's another franchise that has probably by now out-shined the Halo series for cultural impact. (And maybe worth arguing that it probably contributed to Halo 4's dumb "Press button to beat the Didact" QTE?) I'd even put 2011's Dark Souls higher for birthing a new subgenre term, the "Soulslike", even if it took until Elden Ring for FromSoft themselves to hit the pinnacles of financial success and launch success with the formula. And so many other games.