I mean really? another carrier was just announced this week and already we're speculating on t mobile and Sprint? hasn't it been reported that Verizon requested exclusivity as far as new US carriers?
Well, we have to make some sort of guess as to what the 3,3 phone will be.
Nah it was rumored before the announcement but then Tim Cook squashed that rumor.
Those rumors weren't even as strong as rumors for Verizon back in 2008.
Looking back at historical iPhone and iPod touch model numbers, whenever a new CPU is introduced, the major model number gets bumped. The only exception is that iPod3,1 included one model with the last-gen CPU.
I am guessing there are no hard and fast rules for these model numbers.
My theory is that the major version number is attributed to any hardware change that would require a different path in the code. In other words, turning on/off features that relied on a certain speed of processor or amount of memory...such as multitasking.
So yes, it would be a hardware change of some sort, perhaps CPU or memory or some other significant bump. Which brings us back to the 4G or 4S or 4Gs?