At this point, I'd hesitate to say it's that way because they want to retain control. I feel like it's more that the people who run the company can't conceive of anyone not having internet access! I hope to speak with them more about an offline mode, so we'll see how they respond to that.
I don't necessarily use the word 'control" like its a bad thing. My feelings about Apple aside (), I think the analogy works. One of the reasons that Apple products all work so well together is that they retain a relatively high amount of control especially compared to the PC-based platform where it can just be the wild west sometimes.