Admit it, data hogs: you know you should pay more
arstechnica.com
arstechnica.com
Which, usually, is the actual reason for data caps. To generate artificial scarcity in a market where there is essentially no scarcity, and thereby recreate a cash cow.
It's not that caps, or usage-based billing is inherently evil, it's just that the caps were very low, the per-usage rate beyond the caps were very high, and Bell was forcing the independent ISPs that use the network to share the same model, effectively disabling any competitive advantage they might have.
edit: I fear the phrasing of my first sentence may sound like I am arguing against your point, but in fact I am empathically agreeing and just kind of fail at text sometimes.