Let's be real here... There's no doubt that Pixar has benefitted from Disney's name and "synergy". If Pixar had teamed up with anyone else, they would not have had the success they have had with Disney. Box office successes, yes, but Disney's ability to market and cross-promote the films in its park and with its merchandise was a perfect fit.
However, whether Pixar has benefitted in the past is not the point... What's done is done.
I still think Disney is the best fit for Pixar going forward, but its not quite the slam dunk it was 10 years ago. Pixar's name means something on its own now. With five successes in a row, coupled with many less than stellar Disney efforts without the Pixar name, the public is learning. Disney's theatrical releases of films produced by their television animation division do not help their case.
If Fox can take Ice Age and gross $170 million for Regency Pictures, certainly they, or another major studio, could do just fine with upcoming Pixar releases, if they are of the same appeal as past Pixar releases. Pixar could make separate licensing deals for park attractions and merchandising, possibly even with Disney involved.
Public perception is PIXAR is Disney and vice-versa. People will come out to see a Disney/Pixar film because it's Disney/Pixar.
I disagree, but one thing we know for sure... the public will no longer come out to see a Disney film just because its Disney. Yet they are coming out to see Disney/Pixar films, and they've shown they are willing to come out to see a Dreamworks or Blue Sky (isn't that the name of the Ice Age animation studio?) film.
If the Disney name meant that much to movie-goers, Atlantis, Treasure Planet, Return to Neverland, Jungle Book 2, and Piglet's Big Movie would have found greater box office success. Even Lilo and Stitch, for all the praise it received, failed to match any of Pixar's releases, or Shrek or Ice Age.