It wasn't on the network side but rather the business side, where Apple had an unexpected amount of leverage due to its popularity: the iPod was incredibly popular — not just selling well but being a prestige item with an outsized cultural impact — and AT&T was eager enough to get the iPhone that they were willing to give up a significant amount of control over the device and its data plans.

Previously, the U.S. carriers were basically king-makers selecting which devices were available for sale and what features were enabled on them — to the point where I knew a couple of people who imported phones from Europe to get something which either wasn't available from a U.S. carrier or was restricted to one they didn't wish to be a customer of for some reason (e.g. poor coverage), and it wasn't uncommon to hear about people reflashing phone firmware to remove things like the carrier's wallpaper or preinstalled apps which the user was prevented from deleting. I refreshed a phone simply to change the audio codec settings because Cingular had restricted it to the lowest-bitrate which was painfully garbled.

There's a decent (though high level) explanation here: https://www.usatoday.com/story/tech/news/2017/07/04/how-ipho...

It's actually kind of hard to articulate how bad things were in the early-mid 2000s with respect to carriers all trying to push their own garbage and monetize absolutely everything possible.

Thank you for linking the article. I purchased my first cellphone in 2004 so I experienced the era, but I've never used AT&T or an iPhone, so this is all news to me. I also was a late adopter of 'smartphones' and didn't purchase one until 2013 so take my experiences with a grain of salt. (I also visited Japan in '04 and remember being blown away by their phone technology - "large" color screens!)