Here's what you gotta look at. With Wireless carriers the bandwidth available is limited by the spectrum they have available. That spectrum determines how much speed can be transmitted between towers to the base stations, which in turn limits how much bandwidth can be given per customer in an area. In low population area's the networks aren't under much strain. You can see that effect in area's like New York for example. Wired networks aren't generally constrained as much, but there are limits, just nowhere near what anyone can hit right now. Wired is mainly limited by available routing hardware in the line. Obviously the advent of Gigabit switches made more speed available in wired networks.
The problem comes with Wireless bandwidth when people are constantly streaming video for example, which maxes out a connection and keeps it there until you're done. And I hate to say it or be this way. But I'm gonna say that it's very unlikely for someone to use above 4-5GB on their phone unless they're streaming constantly, or using their phone as their primary internet through tethering.
I have grandfathered unlimited on my phone, and I've rarely gone over 3GB, and I've only got close to that when my regular home ISP was down and I was tethering to get online. But, I also rarely use my phone to watch streamed movies. Don't get me wrong, I do go on youtube often, or watch music vids.
Wired networks though, you have to remember cable companies offer their own TV services. A lot of people use cable internet to stream off of Netflix, Hulu, and other sites, thus making it not necessary for you to buy cable TV service, or sat service in regards to people with DSL.