There are no drive-by-wire brakes in the US or Europe for regular cars. Your car's actuator moves the piston that is mechanically linked to your pedal.

So even if the electric system fails completely, you can still actuate the brakes.

You can split hairs all you want. In my car the master cylinder that is connected to the pedals is only connected to the brake hydraulic system through a parallel (i.e. redundant) set of normally-open valves that are closed by solenoids when the ECU starts. When the ECU is functioning normally, the brake pedal is a video game controller, totally isolated from the hydraulic brake circuit by the closed master cut valves. In this normal operating mode, only the computer can pressurize the brake system using its second master cylinder, driven by an electric motor.

When the car is off or the system loses power, the master cut valves return to their open position, and the brakes are pressurized manually, like an old car without power brakes.

This is "brake-by-wire" to everyone, except apparently you.