" they wouldn't be getting sued and aggressively pursued for takedowns"

I don't think so. That behavior only tells you the modest cost of sending takedown notices/threatening letters is less than the (supposed) lost revenue. Kids I know (I'm a teacher) don't seem at all aware of it when complaining about textbook costs and I kind of vaguely hint they look online for it--nothing like the popularity of napster.

To get the DOJ and FBI to move on on this takes a lot more than submitting paperwork, costs a lot more too.