The NY Times article basically blames the AT&T network. It's just not robust enough to transfer larger amounts of data demanded by iPhone and other smartphone users. The release of the iPhone has largely exposed this vulnerability.
In my experience, at certain events where several thousand people are amassed all at once, AT&T data service becomes almost non-existent. I noticed this a couple times last year, once at the Petit Le Mans event near Atlanta, and again at the Concours d'Elegance near Jacksonville. Voice calls worked well, but data connections were not happening at all. So get a couple thousand people around a single AT&T cell tower, and you've got serious data fail.
It all seems to come down to bandwidth. With a lack of bandwidth it's obvious why AT&T is delaying MMS and tethering options for the iPhone.
Although my issues at home are due to a weak signal, I'm still plagued by lack of a data connection and dropped calls.
It's probably time for another call to AT&T customer service.