They also left space for referees to fill in the gaps. This gave us flexibility to shoehorn things into a campaign. It's also occasionally a bit annoying, but necessary -- there's not enough room for everything you want in a Double Adventure. (If it wasn't necessary, the world map was omitted).
But Wil and Bill's point stands. The LBB Adventures are resources to be mined.
I'd like to point out the starships in particular. LBB1-3 didn't have room to detail them, so they were released as a bonus for the adventures. That's how we got deckplans, crew stations, and general operating information for the Kinunir, Lab Ship, Scout, Far Trader, Merchant, Liner, Safari Ship, Mercenary Cruiser, etc.
Nowadays, many of these deckplans are available on the web (or via reprint), and don't have to take up the significant chunk of space they did in the LBB adventures.