All the talk about Apple’s next U.S. iPhone carrier once the AT&T exclusivity expires appears focused on Verizon Wireless.

There are some good reasons for this: VZW has the reputation of having the best network, partially for its consistency in CDMA/EVDO in combination with its 850 MHz band. With 89 million wireless customers, VZW is 9% larger than AT&T’s 82 million wireless subscribers. Before I get into my argument, I need to make the point that I don’t know when AT&T’s U.S. iPhone exclusivity ends. All indication is that it will take place no earlier than 2010, but no later than 2012. But
really nobody outside Apple and AT&T knows.

Perhaps AT&T will pay for an extension to whatever the current or recent data were supposed to have been. And the rest of my argument is somewhat dependent on when this eventually takes place.

Let’s assume that the AT&T exclusivity ends relatively soon, say June 2010. Apple would then have the choice to spread the iPhone to all U.S. carriers, or only some. Which one would be Apple’s highest priority?

My contention is that it is in Apple’s best interest to make Sprint/Clearwire its highest priority, if it could do so relatively soon, say by mid-2010. The common suggestion that Apple should go with VZW is misguided: It’s not that Apple needs VZW. It’s that any carrier needs the iPhone. From this perspective, it can be said that it is the iPhone that makes any carrier.

The Critical Question: What does this mean for Apple?

Verizon Wireless will not offer Apple a technology to differentiate itself against the competition until mid-2011 at the earliest, perhaps mid-2012. But Sprint/Clearwire does, already today!

Therefore, if the AT&T iPhone exclusivity ends meaningfully before mid-2011, Apple would be best served to launch its next version of the iPhone on Sprint/Clearwire.

Imagine the superior services a Sprint/Clearwire WiMax iPhone could offer: Flawless low-latency VoIP, liberating the consumer from traditional voice plans, videoconferencing, streaming television and laptop tethering without that pesky 5GB monthly cap. All of these things are either impossible or performed with subpar quality on AT&T today, and on VZW before it can offer backwards-compatible LTE handsets no earlier than mid-2011.

Sprint/Clearwire is already working with HTC to launch dual-mode WiMax/EVDO Google. Android handsets in coming months. All of these advantages of WiMax performance in the cellular handset will soon be pointing their big guns full ablaze against the iPhone.

4G networks  – WiMax and LTE  – are nuclear weapons in the hands of operators fighting an escalating war for the next-generation services: VoIP and videoconferencing. Sprint/Clearwire will detonate the first bomb in this competitive quest in 2010, using the Android platform. If Apple has the ability to join the party, it needs to do so quickly, instead of following the popular suggestion of joining VZW’s me-too EVDO network.

Final clarification: When the AT&T iPhone exclusivity ends, Apple may simply be able to launch the iPhone on all carriers, using all the applicable radio standards in different versions: WiMax, LTE, and 1.7 GHz HSPA+.

But if it chooses only one carrier — for whichever reason — and can do so meaningfully before backwards-compatible LTE handset chips become available, it needs to take advantage of Sprint/Clearwire’s WiMax network in order to not slip behind competitors such as Android and potentially others such as Palm/WebOS and Research In Motion / Blackberry.