Exactly. Theres also the example of the Droid/Milestone or most Blackberry models.
I'm not anti-gsm or pro-cdma or anything, just not a fan of misinformed, illogical argument.
No one is saying it's impossible or that it can't be done, just going from what apple has traditionally why it doesn't seem like something they will do.
One, design is one of the most important aspect for apple when they sell a product. If you add a CDMA and EVDO radio to the iPhone, it will not be quite as thin as it is now. They would have to make a completely different handset.
Two, they like to streamline their products as much as possible, that's why you only get limited option when configuring a Mac and why they when with a pentaband 3G chip, to streamline their production line.
Three, CDMA may be around for a while, but EVDO will be replaced with LTE shortly, and while it will still be around, it will probably get killed of sooner than CDMA. CDMA is what as being used as the voice while EVDO is strictly data. EVDO has also reached it's peak, which is slower than what carriers have released as GSM 3G. EVDO is the true dying technology and we all know how apple feels about supporting dying technologies.
Four, when verizon finally launches LTE, it won't just be a miraculous switch and suddenly the entire verizon network is LTE. It will take time. Remember how apple waited an extra year until 3G was more widespread before they released the iPhone 3G? And again, even after verizon launches LTE, they will still be using CDMA as their voice protocol, and they would still have to include an EVDO radio because CDMA data is even slower than edge.
Five, Steve jobs will hold a grudge, and if the reports of verizon rejecting the 1st iPhone are true along with the jabs verizon has taken with their driod marketing, it's possible he wouldn't allow it out of spite.
Now, I'm not saying it wouldn't be feasable or unprofitable for apple to release an iPhone on verizon, I'm just saying the it doesn't seem likely given apples history and tendencies.