There are already some Disney movies showing up on Netflix and there are definitely Disney shows.
Yes, I think you are right. It all has to do with newer vs. older movies. Here was part of article I read:
Why 2016?
Currently, Disney is locked into a deal with Starz that ends in 2015. Netflix outbid Starz for future rights to the titles, so it begins when the current deal expires. In February, Netflix’s streaming contract with Starz ended and many favorites, including some Disney flicks, left the service after four years together.
Netflix normally gets their titles from the major Hollywood studios, but not until long after the movies and shows have been made available to cable network providers – typically after DVD/Bluay releases have slowed down. This new deal means newer releases will be available soon after the films are released on DVD.
What about right now?
While you may have to wait a couple of years to get major titles faster, Disney and Netflix reached a separate deal to bring some older films to the streaming service immediately. Look for classics like Alice in Wonderland and Pocahontas. Direct-to-video movies will be available on Netflix starting next year.
The exclusive rights deal is great for Netflix users, but not so great for other pay-TV channel subscribers. This now makes Netflix a direct competitor to traditional channels like HBO, Showtime, and Starz. It’s also bad news for Amazon Prime and Comcast users, who may have to pay an extra $8 a month on top of their cable provider bill to access the Disney collection.