All the points so far here are valid. However, why do people need speeds over, say, 100Mbit/sec for iPhone use? Seriously. I'm honestly asking and not trying to be snarky.
I get that people always want faster speeds in general. But what are you using an iPhone for that needs 800Mbit or Gigabit speeds? Maybe uploading a video to Youtube I guess (and if the carrier supports that upstream gigabit speed) but for practically all other apps (email, text, social media, youtube, movie streaming, etc.) you should be more than fine at 100Mbit. If you're using your carrier plan as your home ISP and/or tethering through your iPhone, ok, I get that...but that's not cell phone usage.