If they intended it to be 100 GB/month, why did they sell it as unlimited?
Roping in customers and competing with sales words that other companies were using.
Long-term fallout is that they have customers leaving and their bandwidth availability decreasing because of increased utilization. Wait, the other companies are the same!
I imaging the model like breathing - Verizon can suck up a bunch of customers but eventually will have to accommodate for the saturation; customers get pissed and leave to go to another company. Other companies then breathe them in with sales tactics and short-term goals (1 year minimum term is the goal). Then, Verizon does something to please the pissed and the other companies do something to piss their customers off. Customers leave those companies and switch to Verizon. Repeat process.
I see this as nothing but (pardon the pun but it fits perfectly) giving themselves breathing room to suck up the next wave of customers with something "Newest/first/best/fastest/blahblahblah". It'll only last a year before those customers see they're getting screwed or the other companies have made a really awesome place for those customers to transition over to. Inhale, exhale, inhale, exhale. Repeat and avoid doing that ONE BAD THING that will ruin you forever (I'm thinking of Sprint/Nextel right now. Such bad smokers they can't afford to put up more towers/obtain space, so they breathe very lightly and get worse every year with more and more customers leaving). ;)
"5G" is the next big thing that everyone is going to sell like hotcakes only to start the breathing process in motion again.