said by Tx:
It can't be, they said unlimited was pointless as 95% of their customers never hit their caps.
Many people who buy into unlimited do so simply because they do not want to worry about how much they use but still wouldn't go over their caps by much (if at all) even if they did not buy into unlimited.
With the $10 unlimited (after $20 bundle discount), getting unlimited even if you do not need that much is not that hard a decision to make if the prospect of paying an extra $1.50/GB beyond your cap (or going with a 3rd-party ISP) scares you. For the incumbent, this is a guaranteed $10/month extra instead of random amount between $0 and whatever the overage cap is.