I'm thinking in terms of f=ma, or the equivalent in terms of torque. I can live with my car getting up to highway speed within a much longer time duration than how quickly it needs to slow down if I hit the brakes. So the brakes need to exert more torque on the wheels than the motor does.

Putting a motor on each wheel could have some performance benefits, but I'm not sure I'd pay for it if I could get a single-motor car for cheaper. I'm talking about "econo box" performance, which is all I want anyway.