I feel like the full self driving cars should have a "budget". Every time you drive, say, 1000 km in FSD, you then need to drive 100 km in "normal" mode to keep sharp. Or whatever the ratio / exact numbers TBD. You can reset the counter upfront by driving smaller mileage more regularly.
That's not solving the right problem. That keeps you sharp driving, but does not keep you sharp supervising. If the car did drive you 1000 km flawlessly, but can still kill you with a random erratic bug on the 1001th km (or on the 1234th). That is where people will zone out. Keeping people driving will keep them able to drive, but won't make them less zoned out when they are not driving.
