I completely agree with you. For any service that has continuing costs, you need to find a way to have continuing revenue. A single purchase for a game that has continuing server costs is a very poorly thought out model.
What I mean by "repurchasing" IAPs: Every app I've interacted with forces you to go through the motions of purchasing IAPs when you get a new device. You aren't actually charged, since Apple knows you already bought the item.
I also fully recognize that my familiarity with these APIs is cursory at best.