Fallout 4 is so big I am pre-emptively weeping over composing the guide.
So how big is Fallout 4? really, really big. Too big for Bethesda staff to have explored it thoroughly.
“I’ve played the game probably 400 hours, and I’m still finding stuff that I haven’t seen yet,” lead producer Jeff Gardiner said during an E3 2015 roundtable reported by gamesradar.
In the full article there’s a pretty cute comment from Todd Howard about wondering who had built the things he’s found in-game.
It’s pretty common for individual development staff not to have seen absolutely everything in their own games. Bungie divides its Destiny teams up both by activity type (PvE, Raid, PvP) and content roll out (House of Wolves, The Taken King). Ubisoft has separate groups working on different aspects of Assassin’s Creed games (Ubisoft Singapore built the naval gameplay introduced with Assassin’s Creed 3, and side content isn’t produced by the main quest team).