I can't imagine how electric brakes could be cheaper than hydraulic calipers. Existing brake calipers are dirt cheap.
Now, when you add the cost of the ABS/TC/DSC system module, maybe it works out better, I dunno, but the amount of copper you'd need in 4 separate electric brake motors would be pretty high, so I don't see how they'd be cheap.
The real advantages for a 48V system are weight and size of existing electric systems. Modern cars have a lot of motors, including now the power steering system (run by a motor attached to the steering shaft). These can all be downsized with higher voltage, saving copper ($$$) and weight. There's also smaller motors in the car, like those in the seats, and in luxury cars there's all kinds of motors (for opening and closing doors and liftgates, adjusting the steering, etc.). Finally, the wiring weight can be reduced all over the car, as well as the wiring cost (since again, copper is very expensive). Your statement about shielding is BS: yes, higher-voltage wire needs thicker insulation, but not that much going from 12V to only 48V, and insulation jackets weigh very little compared to the copper inside them. Furthermore, with a reduced diameter of the copper conductor, the diameter of the insulation will also decrease, so the insulation weight will probably be the same, if not a bit less. Besides, I'm pretty sure most wiring used on cars these days can handle hundreds of volts, and is sized not for electrical insulation properties, but instead mechanical properties (they make it thicker and tougher to handle being handled during assembly and repair, and also so it doesn't get worn through from vibration over the car's lifetime). If they actually sized wire insulation for only 12V, the wires in cars would barely have any insulation on them at all.
Now, when you add the cost of the ABS/TC/DSC system module, maybe it works out better, I dunno, but the amount of copper you'd need in 4 separate electric brake motors would be pretty high, so I don't see how they'd be cheap.
The real advantages for a 48V system are weight and size of existing electric systems. Modern cars have a lot of motors, including now the power steering system (run by a motor attached to the steering shaft). These can all be downsized with higher voltage, saving copper ($$$) and weight. There's also smaller motors in the car, like those in the seats, and in luxury cars there's all kinds of motors (for opening and closing doors and liftgates, adjusting the steering, etc.). Finally, the wiring weight can be reduced all over the car, as well as the wiring cost (since again, copper is very expensive). Your statement about shielding is BS: yes, higher-voltage wire needs thicker insulation, but not that much going from 12V to only 48V, and insulation jackets weigh very little compared to the copper inside them. Furthermore, with a reduced diameter of the copper conductor, the diameter of the insulation will also decrease, so the insulation weight will probably be the same, if not a bit less. Besides, I'm pretty sure most wiring used on cars these days can handle hundreds of volts, and is sized not for electrical insulation properties, but instead mechanical properties (they make it thicker and tougher to handle being handled during assembly and repair, and also so it doesn't get worn through from vibration over the car's lifetime). If they actually sized wire insulation for only 12V, the wires in cars would barely have any insulation on them at all.