Package reasons, probably.
Moving the weight closer to the middle of the car has some benefit too, iirc., but "packaging" is generally the primary factor.
I think there are performance cars with the front caliper at the back of the wheel, and the rear caliper at the front, such as a Corvette, 911, etc. That is, the weight is towards the center of the car.
In fact, some cars moved the brakes all the way inboard, up against the transmission, to get the weight in the middle of the car.


 
				
		