Lalato
Adventurer
That would be true of Greyhawk, Dark Sun and maybe even Planescape, but this is not the reason why people have chosen the Realms for some decades now. People like Forgotten Realms because it is highly detailed. If you won't bother to give lots of information, you'd be better not bothering with the Realms at all. As I said earlier, it's possible to play with older supplements, but saying "look, we have this earth-shaking event that is changing everything, but we're not describing it" is just stupid.
Oh... I agree with you that it's silly to not describe it. But since they aren't describing it, the best assumption to make is that it turns out exactly the way you want it. If this conflicts with some future campaign guide so be it. It's not like there haven't been other events that have put the canon material at odds with what is happening at each gaming table.