While I'm sure ISP execs are all mustache-twirling villains, what they're doing is not absurd, it's essentially the same as selling a burstable connection with

While I'm sure ISP execs are all mustache-twirling villains, what they're doing is not absurd, it's essentially the same as selling a burstable connection with a certain average bandwidth (the cap divided by one month gives a data transfer over time). And the reality is that, as a customer who loads a 5MB site and then spends 2-3m reading it, I much prefer this model than if they sold me a smaller fixed data transfer over time. That networks don't work like this is rather irrelevant, because it's a shared pipe. If they sold be a data transfer over time (say, guaranteed 256kps), that would be wasteful, because I couldn't take advantage of the higher speeds when other customers weren't using it too. A well-managed burstable connection is a much more efficient use of the resource.