Everyone "can handle" arbitrarily much busywork. Whether the lights are on or anything is happening intellectually is another story. I would like to see every American teenager have that experience, but my experience was that in high school, the very top of the class caught glimmers of it occasionally.

I think when you send "everyone" to college, it's going to be no different for them than high school was for "everyone" (and for the smart kids in their less-special subjects): chug through the tedium with as little of your brain as possible, while away the hours and the months until you get to something you actually care about. That's a reasonable way to warehouse teenagers while their parents are at work, but 18-22 year olds could plausibly be doing something else.