Overselling to customers and then capping their bandwidth because you don't have the capacity is bullshit. Normally a customer would go elsewhere, but many people don't have a choice because Crapcast is the only provider in their area for "high speed" internet. (If you can call it that).
If you want a dedicated line, you have to pay for a dedicated line. A dedicated T-1 costs more than cable internet, and it's limited to 1.544 Mbps.
Overselling makes sense, from an economic standpoint. Not everyone is going to be using 100% all the time, so building the infrastructure to support that is wasteful. Take telephones, if everyone tried to make a call at the same time, the lines get jammed. It makes no sense for telcos to buy, install, and maintain all the necessary equipment to allow everyone to makes calls simulatenously.
There are basically three options going forward:
1. Status quo. A very small segment using a disproportionately large ammount of available bandwidth and negatively impact the quality of service for a larger number users. To combat this, ISPs occasionally boot the biggest offenders.
2. Metered access. Pay for how much you use, like other utilities. I think this would have a "chilling" effect on progress and futher delay things such as digital distrubtion of movies (especially hi-def.)
3. Throttling. During periods of high traffic, heavy users are capped to allow other users to use the service they're paying for. During off-peak times, all users are allowed unfettered access.
Personally, I think number 3 is the best option as it still allows heavy users a chance to get good speeds during off-peak hours.