The iPhone revolutionalized touchscreen smartphones. It was the first very succesful capacitive touchscreen smartphone. After that, UIs had to get ready for capacitive touchscreens. Before that, resistive smartphones existed, but did get popular. Websites, for example, hardly optimized for these. They did optimize for the new capacitive touchscreen paradigm, as did smartphone 'apps'.
Prior to the iPhone you could buy a $5 a month unlimited data plan addon from AT&T. The revolution was AT&T increasing unlimited data to $20 a month for the OG iPhone and $30 a month for the iPhones thereafter.
It's weird to look at this in the context of Google and T-Mobile almost shipping the first Android devices with a $10 a month unlimited data only plan...
