Using Spout Lore to reveal a detailed, pre-created world is contrary to the rules.
There is a caveat I should make here. I'm going to talk about rules the GM has to follow. You're welcome to not consider them binding rules, but DW as designed does. If you don't follow the GM rules, you're "voiding the warranty" on the game and it will not operate as advertised. You're on your own then. (Incidentally, this is a close paraphrase of the designers [on p. 159 and in various conversations] – it's not just me saying so.)
For reference, these are the GM's responsibilities:
- Describe the situation
- Follow the rules
- Make moves
- Exploit your prep
… plus following the Agenda and Principles.
So part of your job is to "exploit" your prep, as in mining it and twisting it for the benefit of the current game session. You also have to follow the rules, which includes your agenda. And your agenda is (p. 161):
Your agenda makes up the things you aim to do at all times while GMing a game of Dungeon World:
- Portray a fantastic world
- Fill the characters’ lives with adventure
- Play to find out what happens
Note that doesn't say create a fantastic world – "portray" is a very deliberate word choice, as we can see by continuing the same quote (emphasis mine)…
Everything you say and do at the table (and away from the table, too) exists to accomplish these three goals and no others. Things that aren’t on this list aren’t your goals. You’re not trying to beat the players or test their ability to solve complex traps. You’re not here to give the players a chance to explore your finely crafted setting. You’re not trying to kill the players (though monsters might be). You’re most certainly not here to tell everyone a planned-out story.
So that's the trouble you're having: Spout Lore does let you, the GM, reveal a detail, but Dungeon World itself doesn't permit you to have revealing a big pile of pre-crafted details to be part of your agenda. Spout Lore isn't a opportunity to infodump on your players. In fact, it encourages the opposite with the agenda "Play to find out what happens." That includes about your world.
So why does Spout Lore not work well with pre-crafted worlds? Because in many subtle ways, the answers that players get won't be as interesting to them. The setting detail revealed existed before the PC did, so it's only maybe relevant or interesting to them and their adventures. (Note that Spout Lore requires the GM to say something interesting about the subject.) You are quite understandably going to be way more excited by pre-created setting details you reveal than the players are. If the Spouted information isn't as interesting as it could be, their motivation to use the move decreases. If it decreases below a certain threshold, they'll start seeing it as a "dead" move – one not worth taking when the risk is getting a miss. Other moves become much better value propositions for the same amount of risk.
Something created on the spot or quickly adapted to current circumstances and the flow of the game will be much more relevant and interesting to the players and their characters. By holding your world lightly in your mind and being willing to kill your darlings, you are serving the GM's agenda better. You're serving your players better, too. You can more easily come up with details that are pertinent, and more easily adapt the loose details you do have in your prep to your players' current game input, and as a result come up with something that's way better because it's leveraging the collaborative-narrative design of Dungeon World.