I think what helps explain this image is that it's likely everything before Cars 2 was already in development prior to the acquisition. Pixar seems to have lost some of their magic, however Disney is certainly stepping up their game.
The aesthetic divide between them is shrinking. I did not like Wreck It Ralph though. Not at all.
Pixar movie quality seems to have dropped, while Disney's have gone up after the acquisition.
http://i.imgur.com/H2s4hVL.jpg
Cars 2 was clearly a release for money (they make more money of Cars merchandise than they do from films), but the other films?