I think the real reason explaining why apple has been able to get away with that is the fact that by (1) denying the issue, then (2) minimizing it by saying its a problem with all other phones, and thus (3) making the antenna problem an industry wide one, they were able to play win some time.

You see, the iphone -- or for the matter, any apple product -- can only be fully appreciated within a specific mindset, by adopting a specific reference frame, or point of view. To me, apple had to restore this my-iphone-has-so-many-feature-i-dont-care-about-the-issues POV that enabled them to initially sell a device with a lot less battery longevity than other competitor in the past.

Playing on time and making this a industry wide issue that is not so important, both allowed them to win more customer but also to allow those to adopt/restore this POV. Thus the more they had owners who just signed a X-years contract to get the new iphone the more they had advocates for their case.

The way I see this : its the ultimate win of the fanboy/evangelist strategy agains't the traditional "be-aware/show-you-care/do-your-share" PR moves.