I live on Cape Cod, not exactly the boonies, less than 2 hours from Boston and have ONE choice for broadband. No FIOS, no DSL, just Comcrap cable (with rising rates every year). They have me by the balls and if they capped my Internet there's nothing I could do.
Because not everyone can get FiOS or any reasonable alternative.
I'm pretty much stuck with time warner (offering 10+mbps downloads) or sbc (best is 3mbps for me and I don't even get those speeds) both for around $40 and I live in Los Angeles. There's a few other options, but not many that are uncapped (or have a more reasonable cap like Comcast's) or are reasonably priced.
If Time Warner ever decides to expand this program I'll definitely be one switching away even if it's something slower. On second thought, the more expensive offerings might be worth it compared to what I use every month and I'm not even counting the BitTorrent (legit or not) traffic, sigh.
Why would I pay $29.95 with a 5GB cap, when I can get 1.5mb/s DSL for $19.95 with no cap
Why would I pay $54.90 for 15MBps with a 40gb cap, if I can get 20MPps FIOS for $39.99.