I don't have pay TV and use netflix/amazon/iTunes streaming a lot. I sometimes have multiple kids watching distinct video streams on different devices at the same time.
I haven't hit the bandwidth cap with my comcast internet-only service yet. I can imagine you need to get seriously into torrenting HD movies to go over the edge.
I think that the parent post was suggesting that the ISPs might increase overage charges, and reduce the bandwidth caps (as in smaller amount before overage charges) as a way of offsetting customers dropping their cable tv subscription (i.e. lost revenue) and streaming more video over their internet connection (i.e. more strain on the ISP's network + maintenance costs).
Google Fiber needs to deploy nationally to stop these cable TV/ISP providers from making up their losses thru bandwidth overages!
That said for me, once I found EDonkey2000/Sharereactor I cut the cord. Cable TV sucks, specifically it's business model!