One can do world building by improvisation. Start small, and create what you need - and keep it. Note down what you did, and after the first campaign you have a decent proto-setting. The next campaign can build on that, maybe start in another area, build that up, then tie the two together.
After a few campaigns you'll have a complete setting, with details, and didn't "waste" time doing it.
Yes, absolutely you can do this.
and, I'm going to lump Imaro's post in here too just to answer both of you:
First, thanks for actually answering the question as opposed to avoiding it or deflecting back at me. Second neither I or anyone else arguing for worldbuilding ever said it was "necessary", as I have said before even a story isn't necessary to just play the game. However you've made a distinction that others such as Hussar have been unable to make for some reason and that is the fact that it can add to the game and isn't necessarily a waste of time.
I've run games like you describe, in fact that's exactly how our C&C game is going right now... but my players know the difference between a world I've fleshed out and one that is being improvised on the fly... they've told me as much. My thing is that if given the time and inclination my worldbuilding adds to the game in a positive manner, whether that is enough to justify the time spent on it is a subjective as opposed to objective thing and hus, IMO, stating worldbuilding is "wankery" or a "time waste" isn't objective truth at all.
Hang on. I've repeatedly said that you can world build and create good games. I've stated that numerous times IN THIS THREAD. Of course you can build a campaign this way. Hell, every friggin' DM for years has been doing it this way. I never, ever said that you couldn't do it.
What I did say is that IMO, your time would be better served NOT DOING IT THAT WAY. That doesn't mean that you can't, or that it will not work, or that it is always bad or anything like that.
What I am saying is that there might be a better way of doing it. I never said any badwrongfun stuff. You guys added all that yourselves. Ok, I did use the term setting wankery in the original post that sparked all this, and I came on too strong, but, jeez, get over it. I've repeatedly stated that I appreciate the work that goes into world building and that it can be a fantastic thing.
I just don't like the fact that it pretty much gets touted as the single best way of doing it. Heck, the 3e DMG puts it as the first step in campaign building. I'm pretty sure the other DMG's do as well. I disagree with this.
Imaro, let me ask you a question then. You said that you are going to take 6 months developing your game world. Not that you have to, but you are going to. If your game, for whatever reason, died tomorrow, would you feel comfortable starting that campaign next week? If not, how long would it be before you would feel comfortable starting to write adventures for that campaign world?