You know, we could make them even cheaper by cramming them so close they share walls and then stacking them on top of each other. And because they're all together, we can call them apartments.

If that is so, what is the point of all that unusable wasted space around thise buildings, other than law requiring it for some randomreasons?

Without that, those buildings could either have high quality outside space that could be used for gardening or a terrace or the area could be reduced.