Problem with the Traditional Animation Argument

As many people know, Treasure Planet was a huge flop for Disney and is often cited as being the straw that broke the camel's back for traditional animation. Many people I know often believe that the string of Disney animated films from the early 2000s failed only due to a lack of strong stories and marketing. While this absolutely affects overall box office take, I feel that this argument is blind to something. Even the traditionally animated films with good stories/marketing all underperformed compared to CGI films from the late 1990s to the 2000s. Anyone remember the film Prince of Egypt? It had fairly strong marketing, good reviews and a decent box office take. However, anyone remember which film came out around the same time? That's right, A Bug's Life. A Bug's Life had the same level of good reviews, but it was a much stronger hit then PoE was. Anyone notice something. That's right, A Bug's Life was the CGI film. I have another example. In 2004, the SpongeBob movie received good reviews and was a mild, if slightly underperforming, hit at the box office. Guess what film surpassed it at the box office. That's right, Shark Tale. A mediocre CGI film beat out a good traditionally animated one. My final example is 2009's Princess and the Frog. Again, this movie received lots of coverage and pretty good reviews, but guess who beat it? The forgettable Avatar and crappy Alvin and the Chipmunks. Both of those films contained CGI. Any thoughts people?