Prior to their Microsoft deal they produced a variety of games with different settings (the Marathon universe which linked to their earlier games and forward to Halo, Myth I/II which were RTS with rich lore, and Oni which was a close-combat game that functioned as a precursor to the likes of Yakuza and Sleeping Dogs in terms of the mechanics).

With Halo, the single-player and lore began to tail off to focus on the multi-player market, and their other settings and styles of games were all discarded in favour of an FPS treadmill.

That’s life for game studios though. It’s hard to survive. Making #2 or #3 of a hit is a lot more likely to make the studio survive another 5 years