I don't run a Forgotten Realms campaign, but I don't think that in any way means that it is dying. Forgotten Realms does have many products out there, and I agree that when I looked over the Serpent Kingdoms, not a lot of the information was Realms Specific, and when it was, it was easily reformatted to fit whatever campaign I wanted it to fit. But quite frankly, all articles or books talking about another setting are like that.
FR receives regular support from great writers, and it is one of the few settings to recieve regular articles in Dragon and Dungeon (though Eberron is seeing some support too, which I applaude). The noevel line is thrilling and the characters great, so FR will never really die, I think Ed Greenwood's creation will not only make a lasting impression on D&D but on the entire genre of Fantasy Literature.
I play my own campaign world, but I regularly use Realms content, and I even have a loophole that allows me to slip in trips to Faerun when I want my characters to get a taste of one of the greatest settings ever.