Actually, I've always seen Halo being more than that. The Forerunners, the Flood, the Halo rings, all of these felt as something magical - we were given tidbits of what they were, they made sense, but never to a super deep level, and this is what I loved about Bungie. 343i, in my opinion, ruined that by giving you lots of info that would you only understand if you read the books. I felt Halo 4 was a overload of information that, imo, should have been left more superficial. But this is my take on it (haven't touched Halo for many years now), I know people who think that Halo 4 was amazing.
I hope Halo Infinite goes back more to the Bungie era of storytelling (I have hopes with Joseph Staten there now).