I have no direct way of determining whether this is true regarding professional work outside of Higher Ed, but I surmise it to be the case. It gives one explanation for the high unemployment rate. Why should a company hire more people when it can work its existing staff to the bone?
An argument can be made, one I don't like but one I should acknowledge, that if a college education has as its main purposes to prepare students for the world of work, then students should learn to keep a lot of balls in the air while juggling (metaphorically), as doing so is a necessary readying activity for the next stage in their lives.
The main argument against, both in work and in learning while in college, is a mismeasurement of productivity, where breadth counts for all and depth counts for naught. This is not the way to maximize the product of the two. It may seem that way however, when overt measures of breadth are readily apparent while such measures of depth are lacking. Then it is easy enough to get caught up in what can be counted - lines on a résumé, if you will. I like to give a bastardized version of Shakespeare to describe the situation.
Learning, learning everywhere
But not a pause to think.
The issue is exacerbated by grade inflation, which causes what statisticians refer to as a "right censoring" problem. In other words, if a student performed so well in a class that a grade of A++++ should be earned, but the maximal grade possible to record is only an A, then there is no extrinsic incentive in place to reward such exceptional performance. A time constrained student will then modulate her own effort down to the performance standard, so as to juggle more balls where the student can then do likewise.
The above is a non-issue for average students or below average students. For them the incentives to get the right (for them) balance between depth and breadth are in place. But for very good students, honors students in particular, the right censoring issue can have a profound effect.
The question then is why doesn't intrinsic motivation right the ship? Of course, sometimes it does. But quite often it does not. I really don't know the answer to that but I'm going to indulge some speculation on this score below.
First and foremost, all of us develop our wants and desires from prior experience that we enjoyed greatly. We would like to replicate that sense of enjoyment and look to those activities that seem to have a reasonable chance of producing such a consequence as a place to invest our efforts. Under this view, the intrinsically motivated student acts \because, fortunately for her, she had formative experiences that opened her eyes to taking a more explorative and creative way to direct her own learning. Such a student then gets to reap the rewards from her early success. The ball jugglers in the crowd, in contrast, are absent such a foundation and pursue the résumé in lieu of that.
Second, many of the high achievers have what I think of pejoratively as Amy Chua parenting. In the parents' conception, school and achievement are about deferred gratification and it is the parents' obligation to push the child hard toward high achievement. The child, out of respect for the parents and a desire to honor their wishes, conforms her behavior to that standard and represses intellectual desires toward self-expression that fall outside of the parents' conception of what school should be about. The problem here may be mainly that the nature of the parenting is defined exclusively by the culture and not at all by the aptitudes and personality of the child. In particular, the parenting is essentially the same for a student who is only average or slightly above as compared to the very good student, who is confronting the right censoring problem. For the latter, the parenting blithely ignores the need for the student to learn to direct her own creative efforts, because the near-term consequence from doing that are very hard to measure. So those early formative experiences, mentioned in the previous paragraph, are less likely to happen. The parenting actually blocks them.
Third, the student has no good role model, whether parent, or teacher, or classmate, or friend outside of school, who places value in what I've elsewhere called Encouraging the mind to putter. Such a role model would not push back explicitly on the over programming. The role model would simply provide much positive reinforcement for an alternative way for the student to spend her time, in a kind of intellectual play that leads to exploration, done just for the heck of it. With the role model the student can engage in the most elemental form of learning - imitation. Absent the role model, the student has to invent the intellectual play on her own. Many are unable to do so.
Ultimately, even if it is hard to measure near term, what honors students should want from college is to grow as much as they can. A deep experience produces growth. If an individual shallow experience does not, why should one believe that many shallow experiences will do otherwise? We are getting this wrong, far too often in my view.
I know this is at best wishful thinking, but maybe if we woke up about this in Higher Ed, employers might do likewise in how they are tasking their better employees.