Something went wrong around 2005-2008 where ISPs became no longer content with the voluntary net neutrality that they practiced for the previous 15 years. Maybe the mythical "exaflood" (traffic demand growth exceeding Moore's Law) actually happened and thus ISPs "needed" to either reduce demand (blocking) or increase revenue (double-charging) to maintain expected profit margins. Maybe mergers between ISPs and content creators motivated ISPs to think more strategically. Maybe greybeard engineers retired and were replaced with suits.