Most people aren't going to think about their internet usage in terms of total data used, because working out how much data a particular site or service will co

Most people aren't going to think about their internet usage in terms of total data used, because working out how much data a particular site or service will cost them is a lot of work and requires knowing technical details that most people don't pay attention to. That results in a market for internet products that offer unlimited access to particular sites, sometimes with restrictions like only standard-definition video in the unlimited video plan. In addition, there's not really such a thing as single-price bandwidth to the entire internet at the scale most large ISPs are operating at - they're setting up peering with particular networks, some of which like to try and push more of the costs of peering onto the ISP side than others.