It's absolutely licensing.

When content is licensed, there are different licenses that are distributed based on who pays and what the service is:

* First-run -- you get to broadcast it first * Syndication -- you get to broadcast second * Digital -- you can also show the product on a digital platform (this was how Netflix was able to do their loophole with Starz back in the day, Starz sold the digital license and streaming license to Netflix because the content owners hadn't specified that such a license was unable to be resold or relicensed -- that' since changed and now it's an extra fee if you want to do that like EPIX does) * Digital streaming -- can be streamed but not watched offline * Rental -- traditionally DVD/Blu-ray * Digital rental -- iTunes, Vudu, Amazon, etc. -- includes offline

Netflix would have to pay significantly more for its content to offer an offline mode. Even HBO, who owns most of its original content -- doesn't do offline because again, the costs would be exorbitant.

EDIT: To be clear I'm not being all-inclusive, as JFB points out below me, there are even nuttier licensing schemes too. And this is before we even talk about international, where you typically have different agreements with every. single. territory.

There are more and crazier ones: exclusive windows for airplanes, hotel PPV, &c.

When you're frustrated by some lacuna in a video service's offering, 99% of the time the feature is missing, the reason is "licensing". Content ownership is going to devolve into small offices of tens of attorneys and support staff, managing these licensing deals. Universal Studios et al will simply be licensees of Jaws properties for their theme parks.

Content ownership is already small offices of attorneys and support staff. Most major IPs are actually owned by small production companies. These production companies are in turn generally wholly or partially owned by the major movie studios.

It's done this way for financial bookkeeping, legal liability, and tax structuring reasons. This type of setup is more popularly known as "Hollywood Accounting" and is the reason why a movie can make hundreds of millions but still yield a "loss." (The studio acts as a distributor and is payed a distribution fee; the IP owning company receives royalties; the production company that actually writes the checks for expenses gets its cut "last" after the income has been redirected to various other entities.)

Licensing for video and music is not the same.

However, it is the same in that if you're ever wondering why a music or video content app doesn't do something, the answer is always "licensing."