Last I checked their 3Mbps plan would cost me $35 or $40 per month. It varies wildly from region to region. My father, on the other side of the country, pays around $55 for 25 down (I forget upload bandwidth) with Comcast...
You're right their faster plans are only marginally more expensive, but it's just an extra expense that I would feel bullied into paying.
Ugh.
My youngest daughter lives in another town, which has fibre optic cable, 250 Mbs for 50 per month.