It's funny you want to argue that no utility company has been sued for charging based on usage, and compare it to Verizon. Well here's the thing.. cell phone service nor Verizon are a utility service. But let's go ahead and make them one and stick them with all the extra crap that comes along with it like providing service over an ENTIRE area like the power company has to do. Then there's the regulations put into place to make it accessible to everyone, which would drop initial pricing.
But that whole conversation is pointless since they're not a utility company. Cell service is a luxury item, you don't need it, you want it. It makes life easier, but is not a necessity. The issue here is that cell companies know this as well, so they get away with pretty much charging whatever they want for it. You want to play, they make you pay.
The biggest issue people have here, is not the fact that they have to deal with a data cap. It's the fact that the data cap is way too low. 2GB is absolutely idiotic as I have stated before. Could you imagine your home ISP setting that limit? Yea, some do have limits, but you're talking maybe 25GB at the lowest, a lot are 200GB if not completely unlimited, and you're paying the same or less than the cell data plan costs. The only thing (usully) that influences prices on a real ISP, is if you want faster speeds. Cell speeds (aside from 4G) don't even come close to a home connection, so we're paying the same for slow speeds AND less data.
Everyone wants to blame it on upkeep, etc, but show some real numbers. If upkeep was that big of an issue, these companies wouldn't be posting billions in profit margins every year. Fact is, there is little upkeep, aside from total equipment failure. Once the infrastructure is in place, it's pretty much pure profit. There are plenty of reports out there that outline all of this and show how much everything costs, so I won't get into it. Bottom line is they're not imposing this limit because it hinders the network, or because the data costs them money. They are doing it because they can, ad it will keep the shareholders happy. Setting the limit to even 10GB would keep more people happy and have almost zero difference in efficiency than the 2GB cap.