When Internet usage gets metered, it's because the carriers think it will allow them to massively overcharge everyone, and take more profit; and they're right.
I'm not opposed to an Internet-as-utility model, where it's metered but there is _some_ mechanism to ensure that the charges are related to cost, and not just made up.
The market _ought_, in an unregulated industry, to be that mechanism, but in consumer internet service provision we have a sort of half-regulated industry, where there is never more than about a duopoly of providers in any given market.
Five years ago this was not as true as it is today, as at the high-end of the market (so only people with a lot of money to burn) people would sometimes select carriers based on what phones were available (hence the value of the AT&T-exclusive iPhone), but with a world where handset manufacturers carry most of the power (and in fact get even a good percentage of the money paid to carriers, due to the subsidy) and all of the best phones are available for every major carrier, this no longer matters: carriers are now dumb pipes to everyone but a small percentage of people living in an area with a major coverage disparity.
Nobody seems to mind paying for precisely metered electricity, gas, or water. But the moment you want to meter internet usage, it seems like people swarm out of the woodwork to shoot it down, even though it seems that the current "unlimited" model is responsible for a lot of our current problems.