The real reason? Well how could a publisher expect to sell a new product when the previous most played one was still broken?
Then why are we still getting updates? I agree that it wasn't fair that we were in 4 years of silence, but, from my understanding, that's because Microsoft only gave them the resources/priority to fix the game so that another game could be added to GamePass and 4K collection.
According to 343 this game is fixed and in perfect working condition. From their point of view, updating the game after 4 years of silence was them doing the community a favor.
There is no reason to believe that MCC will continue to be updated or worked on once Infinite is released.They worked on it well after 5 was released and if the game still isn't fixed by Infinite, then I would... at least hope they would still be working on it.
Because it happens all the time. In fact, it already happened: "Halo 5: Guardians is the fastest-selling Halo game to-date according to Microsoft. The game's launch also marks the biggest so far on the Xbox One, with over $400 million in global games and hardware sales, bringing total franchise sales to over $5 billion."
Quote:If classic Halo players had remained quite and stopped voicing daily complaints about MCC for those 3-4 years, then this game would have never been touched by 343.
You're right, but complaints from a niche group of players (yes, that is what we are) aren't what make budgets. Large audiences do and GamePass's & Xbox One X owners are larger in number than MCC's dedicated critics.