[John]

Originally Posted by SuperNerd256

In a pushing match between 2 cars. both with the same weight, traction, and motors, who would win: A standard car, or a car with power to every wheel?

You could power all of the wheels with Ackerman, which would minimize or eliminate the loss of traction by less normal force on drive wheels.

Or a car with more wheels and power to them, for that matter.

More wheels does not mean significantly more traction, though some people have found small benefits to having more tread on the ground, this effect is secondary to the type of tread and the weight of the robot.

Originally Posted by Ninja_Bait

Ackerman limits your maneuverability

Depends what you mean by maneuverability. It improves your ability to turn while driving at high speeds and move in arcs, but it makes turning on a dime difficult or impossible.
Other than 2008 (which had several Ackerman robots), most games have not required the kind of smooth arcing motion Ackerman is capable of. Most motions tends to be like go-stop-turn-go-stop-turn-go, which is what skidsteer is good at.

Originally Posted by Ninja_Bait

and adds unnecessary complexity to a robot that would be more maneuverable with a much simpler tank drive.

This is the main reason why most teams stick with skid steer. The kitbot is skidsteer, and can be built in one day. Even a custom chassis skid steer does not take very long to fabricate, compared to an Ackerman drive. Additionally, it usually uses steering motors that could be used elsewhere (and if you want to keep those motors down to just one or two, instead of four, you must design a linkage to keep them at the proper angles). Skid-steer's simplicity makes it much easier to have a moving chassis early in the season, and to have more time and resources to use on a manipulator.