This is unsurprising in my opinion as they gave very little notice before launching. Most people are likely stuck waiting for their existing contracts to expire. This 'evidence' also seems very anecdotal.
One of our Apple sources has shared some very sensitive information on first-week Verizon iPhone launch sales with us. It’s quite interesting — we’re being told sales are performing a little under what Apple and Verizon anticipated, and we have the data to show it. Below are unit sales totals from five Apple stores combined (including two very, very prominent Apple stores) showing both Verizon and AT&T iPhone 4 sales during the Verizon iPhone’s first five days of availability:
* Thursday: Verizon = 909, AT&T = 539
* Friday: Verizon = 916, AT&T = 680
* Saturday: Verizon = 660, AT&T = 471
* Sunday: Verizon = 796, AT&T = 701
* Monday: Verizon = 711, AT&T = 618