In the 2E days the huge amount of source material was immersing, altho toward the end of 2E, with Volo's endless series of guides (I mean, how did we not have Outhouses of Waterdeep by the end?) and other books detailing the setting to such minute levels, we had so much material it was getting overwhelming and hard to find an area of the world you could set things in and not have some super-pedantic player hard endlessly about how "that whole area has had blah blah" and "Didn't you read X book last month? The king is dead, how could he be giving us all orders!?". Yes the easy answer w/those people is to say that what hapens in the novels doesn't happen in your games, but it's still irritating.