More critically, Youtube relies on network effects and people using it. Part of the reason we share family videos, educational content, and other things is so it's, well, shared. For me, the reasons to use Youtube-dl are:

1) People in bandwidth-constrained settings. If I post my videos, and colleagues in some countries can't watch them, I'm going elsewhere.

2) Remixing. If I can't make collages of family videos, I'm going elsewhere.

Youtube can serve masters like me, where it's an effective platform for sharing videos I want people to watch, and where the goal is dissemination. It can serve masters like the RIAA and the MPAA, where the goal is monetization and control. It will have a hard time serving both.

I suspect if it tries, people like me will go to someone who caters to us. A YouYesYouNoNotTheRIAAYesYOUTube. If we do, I think there will be enough of a network to start to syphon people off, and eventually, cat videos and Aunt Alice will be on YYYNNTRYYT.com, while corporate video will be on DRMed Youtube.

At that point, we'll have a replay.