IMO Six months from now STALKER will be a has-been footnote but RO will still be popular and in fact bigger and better and we all know that to be a fact.
I've got to seriously, seriously, viciously disagree with you. RO will never gain mass popularity because it's a niche title. In fact, it's a niche niche title. They took an already niche market; ultra-realistic FPS's, and made it even more niche by making it a Soviets vs. Germany WWII setting. If it were USA vs. Germany, it'd be more popular. But just like all niche titles, they will be popular to a degree, but can never break mass appeal because they do not appeal to the masses.
Steel Beasts, The Combat Mission series, Close Combat, Operation Flashpoint, ArmA, RO, adventure games, the list goes on and on. These titles are all amazing, but not everyone enjoys being killed by someone they can't see. Not everyone enjoys crawling through the virtual mud for 500 yards just so they aren't killed.
These titles appeal to people who enjoy certain aspects of games. They do not appeal to everyone. STALKER has a much wider appeal than RO had/has/ever will have. Why? Because it's an FPS that mixes quasi-realistic elements (ironsights, setting) with an exciting environment, mutants, and a bit of horror gameplay, mixed with RPG style inventory/customization.
It's also very accessible. People can pick it up and play it like any other game. This is not the case with RO, as you can tell by the new players who get destroyed and frustrated because they can't make it 10 feet from the spawn without getting mowed down.
RO is great, but other games are better and have mass appeal. RO may be your favorite game, and others favorite game, but the sad fact is, it's
you that are in the minority of gamers.
In six months, who cares, six years from now is what is important. Everyone is pretty much still playing the same game they were six months ago. In six years, STALKER will be what it already is; the stuff of PC game legend, like Half-Life. Because of the game? Not so much, but because of the excruciatingly long development cycle that produced a game that was good, but didn't live up to its potential.
RO will be the footnote. It just cannot compare to the multitude of titles that came out before and after it was released. If they continue the "franchise" it may be a different story.