They're waiting for VR. Half-Life 2 already spans everything cool you could conceivably do with a 'post-quake 2' shooter. Team Fotress 2, Counter-Strike: Glob

They're waiting for VR. Half-Life 2 already spans everything cool you could conceivably do with a 'post-quake 2' shooter. Team Fotress 2, Counter-Strike: Global Offensive, and Dota 2 cover all the neat online matchmaking, micro-transaction, user-created content stuff. They don't want to make Half-Life 3, the expansion to Half-Life 2. They want to make something new. They created something new with Portal, which required them to hone their ability to introduce players to an entirely new game mechanic, but now they have to wait for VR to put it all together.