data caps are actually a very poor way to manage demand and limit Internet congestion. All of the costs of supplying residential broadband are for supporting the peak loads, typically Sunday nights for residential customers. Bandwidth consumed off-peak is completely free; it literally has no marginal costs. If ISPs really wanted to limit their costs and congestion, they would limit speeds at peak times. But if their goal is instead to increase revenue, then making consumers pay $1 or more per gigabyte is an excellent strategy.
When we state the marginal costs of residential wired gigabyte are below one penny, but are not zero, that is because we are making the appropriate costing assumption that some of an average gigabyte is transferred at costly peak times.
Canadian consumers have been outspoken against the excessive charges they face, and hopefully Canadian ISPs will listen to them by raising the caps or abandoning them altogether.