They place the AREA there, NOT the full completed thing. The areas you see are like skeletons and they put them there to finish later on and fill in the rest. They are saving themselves time and so they don't have to rush to put out DLC content. If you want an example of rushed DLC content I'll give you one. CoD; they put out DLCs that take them 3 months to create. 3 months just to put out 4 maps. Bungie has to put out; Missions Strikes Raids New MP maps Over 50 weapons Over 50 new armour That is a lot to try and rush out in 4 months compared to 4 maps. So what they did is create the areas just so they can work on everything else and save themselves time to work on the rest.