Here's a random thought. There's an air duct in front of the tires going through the front fender. I know the driver side has this. Not 100% about the passenger side. Could this duct be causing the dust to be ten times worse on the fronts?
The wheels are fine if you spray them down once a week and easier to maintain with some WheelWax.
What would happen if the air duct was blocked? I wonder if less brake dust would accumulate.