So we should force iPhone users to pay for unlimited bandwidth so that we can try to force them to "do more awesome things" with their phone?

What this argument is not taking into consideration is that some people don't use their device as much as others, and they do so by choice. Plenty of people will take a $10 discount to cut their phone usage a bit, and be happy that someone offered them the choice. Personally, I'm a data-crazed maniac who uses my iPhone constantly (and uses around 900MB/month) but that doesn't mean everyone is (or wants to be).

I'd also argue that there are only a few applications that consume large amounts of bandwidth, such as streaming/downloading audio and video. You can still take full advantage of your phone (with the exception of those two things) and not use much bandwidth.