I will not be surprised if Valve releases a new game using Source 2 this November to coincide with the launch of Steam Machines, SteamOS, the Steam Controller, the HTC Vive, and Steam Link. Steamsteamsteamsteamsteam. There's a lot of stuff all coming to a head right at that time, and it would be the perfect time to release Source 2 and a flagship title for their new platform. Although I doubt it will be Half Life 3, but maybe they'll surprise me.