Not Jobs, George Lucas.

Pixar was created to design custom hardware for what we now call CGI. After Jobs was forced out of Apple in 1985, he bought Pixar from Lucasfilms to create a rival computer company. It failed largely because the brains behind the actual hardware was Steve Wozniak; Jobs was the marketing man.

This failure prompted Jobs to reverse Pixar back to CGI R&D. Around the same time they hired John Lasseter who was fired from Disney for promoting CG animation. On the brink of bankruptcy, Jobs let Lassiter do whatever he wanted. So he created Toy Story.

The financial success of that film, Apple failing without Jobs, and secret bankrolling from Warren Buffett allowed Jobs to return to Apple and set the stage for iTunes and iPod, later culminating into the iPhone and iPad.

Staggs has claimed he couldn't get the Board to guarantee the position of CEO in writing, so he left not wanting to face the possibility of being passed over.

Personally, I think Staggs saw opportunities elsewhere and weighed his choices. Currently he's the owner of an $2 billion investment fund, so he's certainly doing well for himself.