Honestly, I think they could do HL3 at this point as the hype around 3 is basically dead.
This, though, is why you don't end things with cliff hangers.
This, though, is why you don't end things with cliff hangers.
But further, the skills to write a game are different from the skills to manage a game distribution system. It's not like by having the HL2 devs valve was squeezed for cash or resources to expand steam.