If fire wire etc did come in to effect , there will be ways to defeat the copy protection , like the government today who wants to find the information in a pgp encrypted document , they don't set about cracking the file. They monitor emails, and try and guess the keys rather than cracking the encryption. I can't see why some one could not just pair the video device with a "box" which then instead of outputting to the screen would output to another device? Also the water marking company that is bring new video water marking out (see doom9 news) says that due to the basis of the water marking, heavy compression / filtering / adjusting will not effect it
http://www.verance.com/technology/index.html . Still i think there still is hope!
Regard
Cyph