We did a bunch of ambitious things on Halo deliberately to reach out to people. We limited players to two weapons, we gave them recharging health, we automatically saved and restored the game—almost heretical things to first-person shooters at the time. We made the game run without a mouse and keyboard. And now nobody plays shooters the way they used to play them before Halo 'cause nobody wants to.
And we PC gamers wondered why Bungie screwed us over by not releasing Halo 3, ODST, or Reach on PC.
And we also wondered why modern FPS games are retarded. Gee, thank you, Bungie.