I was just listening to a podcast and one of the comments was that the transition to purely online media faces a challenge since it goes against the human desire to collect things.
How many of us have at least a small collection of CDs and DVDs. While all are not as compelled to collect things as I am, we all tend to collect some things. With the "pay per use" method, you no longer will have that option.
I wonder how strong this collection desire is in everyone. If it is as strong as I suspect, this transition may not ever be complete, no matter how much the producers and studios want us to change to renting what we watch.