AutoPilot is already independently monitoring driver attentiveness. With FSD, if your eyes are visible, it's watching your eyes. If it can't see your eyes (or you don't have FSD), it falls back to requiring the driver to apply a small and specific bit of torque to the steering wheel consistently.
The drowsiness alert would be superfluous when it's watching your eyes. It's already going to yell at you if it can't see your open eyes looking out the windshield for more than a second or two.
Whether or not the "steering wheel torque" method is better than a vision-based driver drowsiness alert is probably debatable, but it would be pretty tough to fall asleep while also applying exactly the right amount of torque to keep Autopilot engaged.
OP's point is a Subaru monitors its driver just as closely as a Tesla but over a broader range of circumstances. You don't need Teslas in your jurisdiction to get this safety win.
The drowsiness alert would be superfluous when it's watching your eyes. It's already going to yell at you if it can't see your open eyes looking out the windshield for more than a second or two.
Whether or not the "steering wheel torque" method is better than a vision-based driver drowsiness alert is probably debatable, but it would be pretty tough to fall asleep while also applying exactly the right amount of torque to keep Autopilot engaged.