It's only been 5 or 6 years since episode 2. Not only that, since episode 2 they've made Left 4 Dead, Left 4 Dead 2, Portal 2, Alien Swarm, Dota 2, and the new Left 4 Dead 2 DLC that came out not too long ago. It'll be here guys. They said that after Portal 2 they were going right back to Half-Life.