While I'm sure this is going to come as a massive shock to all of you, during his most recent Reddit AMA Gabe Newell stated that Valve is currently working on a couple of new games! And before you ask, no, Half-Life 3 is unfortunately not one of them. According to Gabe Newell "the number 3 must not be said", but on the positive side it does appear that Valve is interesting in doing more with the Portal/Half-Life universe! Whether this will actually transform into a tangible game, only the future will tell, but it is still good to hear that Valve hasn't abandoned their most interesting storylines.
As for what exactly these new games will be, the only thing I can tell you is that at least a couple of them are going to be VR based given Newell's quote: "The big thing right now is broadening the range of options we have in creating experiences. We think investing in hardware will give us those options. The knuckles controller is being designed at the same time as we're designing our own VR games."
And when asked whether Left 4 Dead 3 is being considered, Gabe Newell responded like a true politician by perfectly dancing around the actual answer: "When we decided we needed to work on markets, free to play, and user generated content, Team Fortress seemed like the right place to do that. That work ended up informing everything we did in the multiplayer space. Left 4 Dead is a good place for creating shared narratives. " Whether this means Left 4 Dead 3 is in development or not is anybody's guess, but given how popular Left 4 Dead 2 is even years after its release I wouldn't be surprised if a sequel shows up at some point in the future.
Left 4 Dead 2 is more popular than Dark Souls 3, Total War: Warhammer, and XCOM 2
Naturally, all of these upcoming games will be developed on the Source 2 platform, which Valve is aiming to improve even further in the years to come: "We are continuing to use Source 2 as our primary game development environment. Aside from moving Dota 2 to the engine recently, we are are using it as the foundation of some unannounced products. We would like to have everyone working on games here at Valve to eventually be using the same engine. We also intend to continue to make the Source 2 engine work available to the broad developer community as we go, and to make it available free of charge. "
And for those of you that had to endure the horrors of trying to find help within the Steam Support system, you'll be glad to hear that Valve is continously working on improving and expanding it: "Since the last AMA, we've introduced refunds on Steam, we've grown our Support staff by roughly 5x, and we've shipped a new help site and ticketing system that makes it easier to get help. We've also greatly reduced response times on most types of support tickets and we think we've improved the quality of responses. We definitely don't think we're done though. We still need to further improve response times and we are continually working to improve the quality of our responses. We're also working on adding more support staff in regions around the world to offer better native language support and improve response times in various regions."
That's pretty much it as far as the 'relevant' answers go, but if you would like to see all of the memes and trivia questions you should head over to Gabe Newell's Reddit account. Enjoy, but don't bother asking new questions as this AMA is now over!