A more likely future is that most content will be new and not controlled by MPAA or RIAA. These legacy content holders will fade from relevance as their content is duplicated beyond their control and, even more importantly, rarely ever accessed.
What do you mean? Comcast/NBC will only let RIAA and MPAA broadcast over their networks? No indies?
Content delivery is controlled by content creating big media IP holders. Obviously they will try to keep competition down, especially new media that understands how the Internet makes information free.
Of course, easy, essentially-free, world-wide distribution will make it harder for RIAA and MPAA to maintain control over the flow of mainstream art.
Viewer-funded (or even mini-investor funded) models could be viable. I'd imagine they could even compete favorably with large production studios if the right structure was found.
Studios might also choose to push for an authenticated scheme instead. Their account gets certified (eg on YouTube), and content on that certified account becomes exempted. There are relatively few hollywood houses that would need it, so it would be easy from a scale point of few to certify them.
DCMA works because it is fast, but fast needs a safety valve. Without that it will get thrown out in court.
"Under the agreement, it appears that internet service providers could be forced to block websites hosting content that infringes copyright ... if a US court were to, say, find that a popular filesharing website was distributing copyrighted Hollywood movies, ISPs in all TPP countries would be compelled to block access to that site."
IIRC this is already the case with the DMCA. I'm pretty sure you have to affirm under penalty of perjury that your claim is in good faith.