I don't think that would necessarily be the case. If ISP's could extract a bunch of extra profit by throttling there's a decent chance that all of them would d

I don't think that would necessarily be the case. If ISP's could extract a bunch of extra profit by throttling there's a decent chance that all of them would do it. Look at mobile providers for an example. Text messages cost almost nothing yet for many years each company charged heftily for text messaging which earned them a mountain of profit. And that's in a segment where there were multiple big players competing on relatively even terms.