Your point stands, but three times as many US carriers is really only 2.5x as many subscribers; AT&T and Verizon each have about 100 million subs and Sprint has

Your point stands, but three times as many US carriers is really only 2.5x as many subscribers; AT&T and Verizon each have about 100 million subs and Sprint has 51 million. Increases in non-US availability notwithstanding, the 2.5x increase in US availability is close to the 2.3x increase in sales. I would expect AT&T sales to be down from the iPhone 4 and Verizon/Sprint to be up. Sprint likely offered early upgrades to most customers who want an iPhone in order to keep them from going to Verizon or AT&T. There's probably a lot of pent up demand on Verizon from users who skipped the mid-cycle CDMA iPhone 4 in hopes of a newer iPhone a few months later. On the flip side, AT&T has been a lot stricter about early upgrades this year, leaving many who spend less than $100/month without a full subsidy until November. This is different from their past policy, where early adopter of the previous-gen iPhone users were granted early upgrades.