"It's ridiculous that in this day and age, people have to worry about their internet usage like it's some kind of limited resource."
The caps are driving additional zero-rating services.
"Unlimited Internet" was always a bit of a misnomer, at least now they're being honest about it
So they can easily get back to fair use by limiting speeds to a couple of megabits. Of course that would kill streaming tv.
Another way of looking at it, you can listen to audio 24x7 and not go over quota. Watching tv all day every day is not going to work.
If you offer data rates where you can afford to offer fair use, then each year you can offer higher data rates. Which is what people like.
Where I live, I see this problem mostly on mobile. You see telcos offer insanely high 4G data rates and a data limit that is low enough that you can burn through that in a couple of minutes.
The net result is that nobody cares anymore. In general, people don't want to keep track of their uses. It makes for a poor experience.