Tangled was so expensive for at least two main reasons:
1. Development on the film was started and stopped at least twice before the final version that was actually made was produced. Much of the production budget includes the costs of writing, storyboarding, and designing versions ofRapunzel and/or Rapunzel Unbraided dating back to the year 2000 that were never produced.
2. At executive producer and original director Glen Keane's behest, extensive research and development work was done to develop both character animation processes that allowed the CGI to evoke some of the qualities of traditional hand-drawn Disney characters and the continued development of rendering engines to give the final film images a painterly look rather than a photo realistic look.
3. Overhead in the early stages of production when the film was gearing up twice with staffers charging to the production.
The actual production of Tangled (the final version that was actually made) would likely cost between $150 to $200 million, similar to but likely slightly above the $150 production cost of Frozen. To be clear, #2 and #3 are where most of the extra money probably went.