But how would a new player even know that?
Probably much like I did. My group has been solidly playing Pathfinder since beta and before that my own experience with 3.5 was kept to just a few sessions. I've become the designated DM to introduce 5th. If you read into the setting material instead of trying to just find the 'latest' setting book on amazon and clicking buy, you'll discover the same facts I have minus the SCN geography bit because that's in the Hoard of the Dragon Queen book. But, as these posts get rolled up into the communal knowledge of the Internet, it will be more common knowledge.
Hello to you who found this post using a search engine. :)
For example, I'm pretty sure Neverwinter still got destroyed[..]
False. It's still there and doing well.