Having an iPhone in your hand does not make you a "nerd". It makes you stupid in my eyes, when I discover you use it only for messaging and calls.
I understand what you're trying to say, but I think there are better ways to say it.
I disagree, though. I have a number of friends with iPhones they use for little more than that, but they were free from their spouse or a family member. They either don't pay for a data plan or the data plan is part of a shared family plan so cost-wise it's a wash compared to dumbphones. They also happen to have a decent amount of storage (though not competitive with things like the iPod Classic until this latest generation of iPhone) so they can carry just the phone and have their music, calling and messaging in one device.
Excuse me if I sound a bit like what Munroe says is the 'revenge of the nerds', but to me a nerd is someone who has very specific interests. Interests which most of the time, alienate most people, since they are specific. You identify yourself not because you own a tech device, but because you are very interested in a topic. I see nerds as producers and not consumers.
Nerds are people who write fanfic,or make drawings of Game of Thrones. Not someone who simply watches a TV show.