This is part of the problem with you guys using AT&T and Comcast for Internet - they're also cable TV providers.
I'll bet you that the bandwidth caps don't include U-verse TV, do they?
This is the whole idea behind network neutrality - AT&T and companies like them implement bandwidth limits and throttling so that your (negative) experiences with Hulu, Netflix, Youtube, and the rest gradually coerce you into consuming all of THEIR content.
It's a difficult subject because ultimately they own the network you're using and should have the right to use it however they want. However, what they're doing is extremely anti-competitive.