Hmmm..... traction.

I don't see how they would be practical. They would have to be considerably more mechanically complex and even worse heavier.

The other thing is this a solution to a non problem? Think about it. Bicycles have large wheels. Generally, large wheels offer good traction. Have you ever even heard of an all wheel drive tractor? Tractors have such big honking drive wheels that they don't need all wheel drive and tractors do pretty well in rough terrain and muddy fields.