In a way what he is proposing is already used for some systems of a car, although far from everything and mostly for lower currents. Some ecus are capable of de

In a way what he is proposing is already used for some systems of a car, although far from everything and mostly for lower currents. Some ecus are capable of delivering enough power from their own I/O pins to drive other components, if any of these outputs are shorted the ecu can detect this, power off the output and enter appropriate failure mode(diagnostics code + disable other functions). When the short is gone it will automatically activate again if considered safe.