Crash fell victim to the demise of "Animals with a 'Tude" popularity. His games were never really all that amazing. They have held up surprisingly well over time, though. Even with Naughty Dog at the helm, Crash's games never reached the levels of fun and creativity seen in a Mario, Sonic, Donkey Kong, etc. (though Crash Team Racing was the best Kart game ever made when it released).
Crash didn't have a creative world, a likeable cast, or any real appeal aside from the fact that he was Sony's mascot and his games were the best 3D platformers the Playstation had to offer (though 2D games like Klonoa and Tomba did it better...). Universal just doesn't have the chops to compete with the big boys. I suspect that if Nintendo let a company make second rate Mario and Zelda games, they would do poorly, too.
Now go bomb some Dodangos.
