Kae'Yoss said:
Like Khelben? Zaknafein? Seiveril Miritar? Sarya Dlardrageth? Matron Do'Urden? Matron Baenre? Fyodor of Rashemen?
You know, while I haven't bought every Realms supplement by a long shot, I do have quite a few of them. Heck, I even have the original gray box!
Yet I only recognized three of those (Khelben, Do'Urden, Baenre), and only Khelben really seems to be significant for the Realms at large to me.
And his death wouldn't have affected any of my Realms campaigns much, since he appeared only in one of them (and only for a short scene in which he persuaded the PCs to sell him the Scroll of Netheril they had found). Elminster, on the other hand, hasn't appeared in
any of the Forgotten Realms campaigns I was involved in.
Not because the DM of the campaign didn't like him. No, it was simply assumed that he was busy doing something else somewhere else while the PCs were having their own adventures.
Too often people seem to forget that Faerun is big. Really, really big. Several times the size of North America big. Frankly, you could kill off every NPCs above 15th level and most people living in the world would hardly even notice. And you can similarly ignore the soap opera dramas of the novels and still have a vast and diverse setting left over that provides fodder for a multitude of campaigns.
So Mystra dies. Which is a bummer for her priests and a source of worry for archmages. But presumably, there are still wizards out there and magic still works somehow, which in the end is what matters most for the average adventurer. And thus you'll still have adventuring parties consisting of a fighter, a cleric, a rogue, and a wizard going off to fight evil, kill monsters, and loot ancient treasures in the same lands of Faerun that gamers have known for ages. Some of the details will be different, to be sure - after all, a lot of time has passed. But many things will still be the same so that it all will undoubtedly the same setting, just like Earth is still recognizably the same world as it was in 1980.