The same kind of logic that you're using to jump from one example to another. Paying for your subs does not guaranteed housing, but it guarantees housing for people who may not even use it? In a 45 day period, when a typical sub covers 30 days? Your sub isn't any more important than mine or revolver bobcat's, but you still want to hold onto something that you may not use and is in limited quantity.
You'd need some sort of reclamation from people who truly don't play the game anymore, espesically if housing in itself is a limited resource (which is definitely the case). No matter how much housing you'd slam into the game, you'll still eventually run out of space and ultimately the number of players who don't even log in (but still have a house) will pile up as occupied space.
