I’m as guilty as anyone—from time to time, I’ve been known to diss AT&T and Apple about the dropped calls and generally crummy operation of the iPhone as an actual phone.

“How’s the Android treating you?” a friend quips. “Does email work today?”

“I’m sorry, I couldn’t hear you,” I respond. “I was listening on your iPhone.”

You know.

Anyway, I always thought it was pretty funny that the iPhone never worked as a phone very well. Until it became available on networks other than AT&T.

Today, CNN ran an article along with a link to an older article that shed light on why AT&T was so bad—and it made perfect sense. In a nutshell, AT&T fell off because its cherished iPhone overloaded its network. And it would have overloaded any network (we could be talking about Verizon right now).

According to a December 2009 CNN article, “AT&T’s data traffic increased 5,000% because of the iPhone.” Also, AT&T’s network was actually the fastest at the time and best able to handle the load of any of the networks.

Piper Jaffray analyst Chris Larsen said at the time that he wondered if Verizon’s “…network has the capacity and backhaul to support a device with an adoption curve of the iPhone.”

Remember all the “there’s an app for that” ads and the snide/clever “there’s a map for that” counter-ads by Verizon? Well, Verizon’s network possibly covered more area, but AT&T’s was actually faster. Perception was otherwise, though, because of all the complaints about the iPhone.

In 2009, AT&T promised big improvements to its network. The company followed through. In 2011, telecommunications industry analysis firm Frost & Sullivan gave AT&T its 2011 strategy award.

While launching a 4G LTE (Long Term Evolution) network, AT&T has also been upgrading its 3G network, and doing a good job of both, apparently. CNN is reporting that AT&T’s 4G LTE network will be “the mobile network standard of the future” and that its 3G network is much faster than it used to be.

In fact, upgrading 3G isn’t something Sprint or Verizon can do with the technology they chose for their networks. (AT&T’s was actually older technology that was upgradable, while Sprint and Verizon’s 3G networks are basically maxed out for speed.)

“AT&T’s network is getting better, and it’s better positioned for the long haul than any of its rivals,” CNN says. “Now it just has to wait for perception to catch up to that reality.”