I remember back when the iPhone came out, this was perhaps the most noteworthy aspect of it, at least to me. We were so used to phones coming with crap on them and tightly coupled to the carrier. If the carrier didn't want something on the phone, it never got there. So Apple comes along and says "Hey, AT&T, we will make you the exclusive carrier for the iPhone iff you leave the entire experience under our control."

There were lots of downsides to that deal, of course, but I appreciate that it broke the carriers' exclusive control over mobile phones.