It seems that as time goes on, more and more people are now coming around to the idea that the Half-Life series will not be getting any official follow up games. Neither Half-Life 2: Episode 3 or Half-Life 3 have been even vaguely hinted at by Valve in any official capacity.
So my question is this. Why has there been no real successor to the Half-Life series?
First and foremost, what is it that we all love about the Half-Life series to begin with? Is it the narrative? The environmental story telling? The moment to moment game play? If you really think about the main plot of Half-Life, the story isn't really all that original.
Science experiment goes wrong. Aliens appear.
Yes, you can dig deeper and deeper into each of those points. The Gman's involvement in the whole thing, how the combine tie into it and so on, but right now we don't have any answers to a lot of the questions.
So what is to stop some other team coming along and making their own Half-Life? What really is the reason that Half-Life holds such a special place in so many people's hearts while other FPS games come and go without a backward glance.
For me it would be this. Half-Life is about variety, especially when compared to modern shooters. The environments, the conveyed emotion, the enemies, the weapons. Every single aspect of Half-Life shifts and changes with every new encounter.
You learn tricks which you use against certain enemies. (Vortigaunts need to charge their attack and will always hit if they have line of sight. Houndeyes charge can be interrupted by attacking them. Headcrabs can be dodged and then take a moment to wind up for another attempt.)
It doesn't SEEM like a modern AAA developer should have any major issue making a game with the same level of variety, but why has this not happened do you think?