Because they are nothing new. It's like Kill Bill, its been done before and been done better than the famous one, only coz the cool ones were banned due to being too violent or breached a copyright and they wernt allowed to show it at main cinemas. And its not what Quentin was trying to do to salute martial arts films becuase if he did then he would be classed as a crap director!
"Shrek" Hasn't been done before. Ever. The fact that it modernizes fairy tales, makes them hip and more marketable to kids and adults alike is what makes it so unique and popular.
"The Incredibles" storyline is what sets it apart from any other animated feature like it, much like any other PIXAR movie. That's their bread and butter, creating incredible animated features with a plausible, family friendly, smart plot from which everyone takes something from.