Of those games you listed in the OP, only one of them was cel-shaded: XIII. Borderlands uses outlines to help define a more comic-y graphic style, but doesn't use cel-shading. Rage certainly isn't cel-shaded. Even Evil Genius, there are noticeable gradients between tones: it is not cel-shaded.
These aren't cell-shaded, they have a particular art style, but are not cel-shaded. Same goes for games like Prince of Persia(2008). Okami was cel-shaded along with 2D art style elements added in, so isn't entirely a cel-shaded game.
Cel-shading is a great way to introduce a simpler art style, getting around hardware issues while still making the game look marginally good. They age fairly well and have allowed the Wii to have some pretty good-looking games. I think cel-shading worked well for the Tales games, it worked for a good many Wii titles, and I think it should continue to be used as an alternative to hyper-realism. On the other hand, I like that games like PoP and Borderlands are taking on a non-cel-shaded, but illustrative style as opposed to realism. It's good sign of artistic diversity and I support it in full.