Yep, exactly. They made all their money long ago and then setup a trust fund to live off of for the rest of their days, called Steam.

Besides there is no way a HL3 would come close to the hype that is on it now. It would be the next Duke Nukem game.

Pretty much. The only real game development we'll be seeing from VALVe is DOTA 2, Counter-Strike: Global Offensive, Team Fortress 2 (and even then part of it is community-developed), and Virtual Reality (though they're more on the hardware R&D side). At this point, a lot of people stopped seeing VALVe as a game developer, and have stopped seeing that way for quite some time. Personally, I see VALVe as an unofficial variant of an incubator for developers who want to work on software projects with potential. What kind of software? I don't know, they do weird crap! Figure that out yourself! Heck you can make a brand new idea from scratch and recruit co-workers to join you! With their cabal system and your requirement to either join one or create one of your own for your own idea of whatever, how is it not a variant of an incubator?

And according to an "insider" people did attempt a sequel to Half-Life 2: Episode 2, only for them to give up because they couldn't surpass expectations on what a sequel should be, so they moved on to projects more interesting to them. And apparently this was a thing over and over again. This really does look like the next Duke Nukem Forever. I wouldn't really be excited for Half-Life. It'll be as awesome as Black Mesa Source's retail Zen world of awesomeness... Oh wait. That doesn't exist either.