puts tinfoil hat on
That's the intention. They don't want it to be fun. Lets review what happened in 2007:
Halo 3 releases and it dominates the Xbox market, like no other game ever has. Halo 3 is still to this day the only console game to be the most played game for three fucking years in a row. And you know the only game that came close that? Halo 2 for two years. So that's pretty good right? Any sane company that looks at this game, they're going to take a spyglass at it to make sure it's retain it's success...right? But was it really good for Microsoft? Lets look at the details.
Microsoft wants every customer to keep buying software consistently. That was not happening for Halo 3. People played Halo 3 for the matchmaking and stayed for the custom games. All night, they played with their friends and had fun. But you know what they weren't doing? Buying other games. Uh oh, we have a problem. The game is too good.
Just look at Gary's Mod and Team Fortress 2. These games are over a decade old and still have a population that companies would kill people to have, games that don't have any modern practices like season passes, SBMM, etc. Why hasn't this model been chased like no other? Because Valve is private and in private companies, money is king. In public companies, consistent growth is king. It keeps the stock flowing. Putting all your eggs in one quarter (even if it brings more money) doesn't look good on the stock market. "Fun" games are cancer to these public companies and they will fall on their sword to avoid it. They are making these games down to a science. They are exactly good enough to get you to buy the game but not good enough to keep you playing because they need you to move on.