But consider the counter-example: Hulu's failed IPO. The idea that these assets are available for sale is an assumption, not a given. The uncertainty of this assumption killed any chance of a Hulu IPO. The TV/film assets are protected by <copyright as monopoly>; and if they can be monetized outside of apple, they will be. That is pretty much in line with the observable data to date.
For a company the size of Apple, to get into content production it would be less expensive and quicker for them to acquire than to build it in house.
And for any good partnership, there needs to be a Win-win on both sides. If Apple were to sabotage it's content agnosticism, would probably hurt it's mobile market share.