This is just a random thinking out loud post, will be followed up later in more detail.
One of the strangest things I have noticed are vehicles (usually luxury think BMW, Lexus and so on) typically having an ugly color cast to the front wheels only. The rear wheels are mostly devoid of this problem. One theory I have come up with to explain this color cast to the front wheels only are the owners using semi-metallic brake pads instead of the ceramic brake pads. Semi-metallic pads costs less but wear out quicker. Ceramic pads are more costly but provide dependable stopping power and YES less brake dust.