We are really only paying for bandwidth to/from our providers. Everything in-between is best effort, nebulous peering arrangements, etc.
> But, ISPs charge their customers for 'unlimited' bandwidth
I doubt you can find a single residential Internet provider who advertises unlimited bandwidth at this point. The marketing for 'unlimited' started to counter dial-up services like AOL who billed usage by connection duration not bandwidth usage.
> having all the major content providers on-board with calling them out on throttling will keep them from doing it
Way more likely ISPs will do a little deep packet inspection and re-write the page to have a message along the lines of "Netflix & Google are the reason your rates keep going up. Your video is buffering because Netflix & Google want YOU to pay more for Internet service"