Sonic and Dr. Robotnik are codependent. They don’t actually want to defeat each other. That’s why Robotnik is always building these elaborate bases that, for some reason, have a bunch of perfectly Sonic-sized tubes for getting around in. And it’s why there’s always that moment at the end where Sonic is chasing Robotnik but doesn’t catch him.
Sonic and Dr. Robotnik are codependent. They don’t actually want to defeat each other. That’s why Robotnik is always building these elaborate bases that, for some reason, have a bunch of perfectly Sonic-sized tubes for getting around in. And it’s why there’s always that moment at the end where Sonic is chasing Robotnik but doesn’t catch him.
This is true for a lot of hero villain combos. Batman and Joker come to mind immediately.