Sometimes, you really should be careful what you wish for.

That's how The Wall Street Journal views AT&T's (NYSE:T) exclusive license to sell Apple (NASDAQ:AAPL) iPhones. This deal with the turtlenecked devil is bringing in fewer new AT&T subscribers than you'd think -- while overloading AT&T's high-speed data networks and making the carrier look bad.

If there's one consistent complaint about the sleek, slick, powerful iPhone, it's the lack of a dependable network. Before the iPhone 3G model was launched last year, it was a popular pastime among tech enthusiasts to buy first-generation iPhones, unlock them, and use them on some other carrier's networks. Analysts tell the Journal tales of sold-out Apple conferences where every mention of AT&T would draw boos from the audience.

The article concludes that Verizon (NYSE:VZ) probably would steal plenty of current iPhone customers from AT&T if given the opportunity. In fact, many pre-iPhone subscribers could make the jump, too. As the Journal concludes, "Whatever value AT&T got from the device, it seems clear that Apple was the real beneficiary."

Verizon's advertising centers on "the most reliable network" in America. At some point, Apple may give Verizon a chance to walk the talk. In the meantime, Verizon's fanciest smartphone is the BlackBerry Storm from Research In Motion (NASDAQ:RIMM), accompanied by a smattering of lesser lights from HTC and Samsung.

While the BlackBerry market is large, it tends to attract corporate users with a milder appetite for data-intensive online video and web surfing than your average iPhone afficionado. AT&T also offers other highly capable smartphones from providers such as Nokia (NYSE:NOK), RIM, and Samsung, but says that iPhone subscribers consume two to four times the data bandwidth of the other smartphone users. In other words, Verizon's network has never truly been tested on an iPhone scale.

Despite the Journal's misgivings, I believe that the iPhone deal has been very good to AT&T. If Apple takes its ball and goes elsewhere, AT&T will be left with a network considerably strengthened by its efforts to keep up with data traffic demand from the prodigal phone. Without the old, heavy load, the AT&T network should be the snappiest in the business -- ready to pick up replacements like the Palm (NASDAQ:PALM) Pre or Google (NASDAQ:GOOG) Androids. The rebuild would be long and arduous, but AT&T would come up aces in the end.

What doesn't kill you makes you stronger. Maybe AT&T should just thank Apple for tempering its networks -- and let the iPhone do as it pleases. Care to disagree? Sound off in the comments box below.

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Fool contributor Anders Bylund owns shares in Google, but he holds no other position in any of the companies discussed here. You can check out Anders' holdings or a concise bio if you like, and The Motley Fool is investors writing for investors.