I'm sorry Fez, but I do not see the business sense in offering only "rentals" of entertainment media, unless they do it at the same price that they sell stuff now. Think about it. In music, their target market for a CD will pretty much have forgotten a CD they bought today within 3 months. Why would they pay to "rent" it again, when there's new music to be had? Think about all the CD's you've sold/given away/are collecting dust...
Similar things go for movies. I buy when it's something I might watch every year or so, but I would not own most of the movies I have now if they "expired" in three months. I have movies I bought a year ago that I haven't even watched yet, so I just don't think I'd bother. I would either catch it when it was on the tube (even in the Fezmid-predicted future where TIVO is banned...) or, if there was a specific time that I'd really want to watch it, I'd rent it from a video store (which I would guess would be cheaper....and how would they rationalize the business case of "battling" with rental stores, which are a major source of income as well).
Think what you want Chris, but I can't envision where there's any rational business justification for a time-expire only business...