I wonder, why we don't just use these automated systems only as safety backups, keeping the driver in full control of the vehicle? If the driver falls asleep, o

I wonder, why we don't just use these automated systems only as safety backups, keeping the driver in full control of the vehicle? If the driver falls asleep, or an animal or child runs out into traffic, or the vehicle starts drifting into oncoming traffic, the automated driving system can take over and take whatever action it deems necessary to avoid a collision, with an option for the driver to forcefully take back control if necessary. The driver can still use adaptive cruise control, and even lane-keeping for short periods of time (5 minutes), but all other aspects of driving (steering, navigation, signalling, braking, etc.) are the responsibility of the driver. Best of both worlds then, with the goal of minimizing injuries and deaths. Is there a problem with this that I'm not seeing? Why isn't this the real goal?