As various broadband providers drool over the idea of implementing broadband caps, they've mainly focused on the claim that they're doing so to make "bandwidth hogs" pay "their fair share." Sometimes they sprinkle this with claims of poverty over having to provide unlimited access to people who actually use it a lot. Of course, none of this is true. The various metered broadband plans almost always end up increasing everyone's bills, and there's little to no evidence that bandwidth hogs are a problem, either technologically or economically speaking.
For the most part, broadband caps are really about protecting video revenue. Many broadband providers these days also provide television, and that business is a total racket these days, with TV companies rolling in cash. Internet TV breaks up the artificial monopolies and the monopoly rents they can extract, so the last thing the broadband (and TV) providers want to do is make it easier for consumers to route around their television programming and access it directly on the internet.
As if to highlight that very point, Canadian telco giant Rogers decreased its already very, very low broadband caps just as Netflix announced that its streaming service was coming to Canada. The timing may be slightly coincidental, but it certainly highlights the point. Rogers doesn't want you streaming videos on Netflix if it means you might not watch Rogers' own TV programming.
Time To Face Facts: Broadband Caps Are Really About Protecting Video Revenue | Techdirt