In a post from GigaOM by Stacey Higginbotham, the various reasons Apple could have to drop the SIM is discussed. You should read it. Here is a part:
Earlier this week, I reported on rumors that Apple and Gemalto were developing a SIM that Apple could integrate into its iPhone motherboard. In the emails, comments and phone calls that have poured in since then, I’ve received confirmation of the rumors, (although still no word from Apple or Gemalto) and gotten a lot more context about what this move might mean.
While the idea of Apple cutting out mobile operators by selling the device with a SIM already inside — and the ability to choose your carrier via an App Store download — is the most obvious option being discussed, there are plenty of other options that might also be on the table, from a mobile payment scheme to Apple launching its own bid to become a cell-phone company that uses other carrier networks. Let’s break it down.