Sure they could, but one might hope the AT&T's eroded trust would serve as caution towards other overly cooperative companies. Or encourage companies to fight in court to be given the transparency allowances they desire to let the rest of us know they are legally compelled to do this and in no way do they agree or are doing anything beyond what's required.

Granted, like FB issues and others, we in this community need to realize that most users simply don't care (even many b2b ones) and not get upset when our users don't move their dollars on principle. For us it's a big deal, for many there are real, harmful issues going on in the world and volume collection of data by companies and governments is not one of them. And we can't make it so despite the deluge of articles by a supportive mass media.

EDIT: To clarify, you mentioned "other ISPs" but I want to be clear I'm talking about private pipes and not residential internet though I know they are often shared.