Toy Story and Shrek are kid's movies; so you're not refuting her point about the American mindset that animated = for kids. To be fair, Toy Story, Shrek, etc, got inflated ticket sales because they were targeted towards kids, but the parents had to buy tickets for themselves as well. They were great movies, but they did receive a decent amount of "help" from being targeted towards kids. Spirits Within was targeted towards adults(part of why it failed), and you're completely out of touch if you think there still isn't a social stigma of "cartoons = for kids" in America.
Spirits Within failed because it was called Final Fantasy, period. Opinions of the quality of the movie are irrelevant; it was the name that killed the movie. Every review that I saw about the movie at the time all started with "I didn't want to see this since I never played the games so I wouldn't understand what was going on." Most did not say the movie was bad, although there was a few that said that the graphics were so good they would distract you throughout the movie.