I like my world to be much, much more involved. That's why I love the Forgotten Realms.
I can guarantee you that your thousands of pages of Realms notes do not make it more 'involved' than my Apocalypse World, which features a map which we can all see, with notes that anyone can add to and a list of names of all the NPCs we've met.
Because involvement comes at the table. And only at the table. The lonely fun of reading bad fanfic dressed up as 'background' and dreaming how much fun it's going to be to surprise the players with it, is often presented as a 'living breathing world'. But that's nonsense.
A living breathing world only happens at the table, and only if the players care. And if you've let them build it, given them a stake, they care. Put me or any of my players in 'The Realms' and none of us could give a monkeys. Unless I can have my own bar in a town called Bad Fanficville.
If you're playing a modern day cop story, and trying to work your way into the city's underworld, there's a lot of things that are going to act upon you.
And if you read a game like The Dresden Files you'll see how to build a multi-layered, complex and dynamic setting filled with interesting characters in conflict with each other and how everyone knowing about it enhances the game. Because when everyone knows - that's part of the game. Secrets are not gameplay.
I'm great at building layers upon layers of plots, events, organizations, and such. I love doing it, even if it doesn't make it into play. But a lot of these techniques are very helpful in running a good game.
I think this is the real point. And a lot of D&D players, especially GMs, are the same. They love the prep. They love the reading. They love the imagining. All that is great. None of it is the game. The game is what is shared at the table.
[MENTION=42582]pemerton[/MENTION] was making exactly these points about 'living breathing worlds' not aligning with pre-authorship. They can be created in the moment, and be beautiful, poignant, deep and complex. It's okay to not believe me, but it's true.