in a 200 sq ft apartment is very very crowed, but the room is still far from filled. You don't have to wait for the apartment to be saturated: - squeezing one more people in will have to push another out - before you move out.
It doesn't have to be 耗尽. When it reach a certain degree shortage of resource is enough to cause wars and lives become very difficult. You want to avoid that preemptively.