Instead they have announced the spiritual continuation of the series in an upcoming title Survarium.https://twitter.com/gscstalker/status/195182555899756544
More details in the already-enjoyable developer video diary series:
As much as I am saddened by the discontinuation of Stalker and as much as I am suspicious of a F2P MMO, I am actually looking forward to Survarium. I have a lot of faith in these developers to do what's good rather than what's right. As Chris Remo (Idle Thumb and Double Fine's new community manager) briefly describes in this MolyJam-related video, part of what was great about the Stalker games was that they were hard, confounding and often unfriendly.
This is completely unlike the flat, accessable, hand-holding, objective-marking tradition of modern western FPSs in general and MMOs in particular. Call of Pripyat, the most recent Stalker game I played, was a game about loneliness, desperation and thwarted redemption. Desolate, depressing and awesome. One of the best open-world games of all time, in my opinion.
This is not to say that a more directed experience (if done right) is antithetical to the post-Soviet, post-appocalyptic setting I so love. The more recent Metro 2033 was highly linear, for example. But this fact actually helped to bring out the enduring humanity in the otherwise overwhelming harshness of a nuclear winter, which was the main theme of that game.
Still, there's nothing quite like slotting your final filter into a cracked and frost-covered gas mask with nothing in your ears but your own laboured breathing, the freezing wind and the relentless click of your geiger counter to really focus the mind.
Anyway, I digress.
The GSC Stalker team continues as Vostok Games. While I wait patiently until the Stalker Complete 2012 mod gives me an excuse to play the whole series again, I will keep watching Vostok from outside the exclusion zone.