Because they have some serious skeletons in their closet as well: such as a nasty little predilection towards hobbling devices (disabling bluetooth functionality, wifi, forcing their own crappy proprietary software onto phones, etc). As much as people like to think the grass will be greener on the Verizon side when they finally get the iPhone I'll believe it when I see it. I hate AT&T's horrible service with a passion. I'm just not convinced Verizon will be our savior.
Finally they grew a pair or woke up or whatever, these spots are hilarious... (I know this is not true, but) I look at them as someone finally standing up to the Mac PC ads lolz~