Academia in research institutions was never meant to be a 9-to-5:30 job. While a day in the life of a graduate student can be grueling (or look like grueling), the numbers of hours one puts in during this period is not significantly higher than someone who practices cricket every day to join the Indian cricket team.
Intelligence alone is often insufficient to succeed in any job. In the book, "Greatness: Who makes History and Why?", Simonton quoting the famous Anna Pavlova says "Success depends in a very large measure upon individual initiative and exertion, and can not be achieved except by the dint of hard work." He further says,
Only clock watchers and time card punchers put in just 40 hour weeks. Creative output in the science correlates positively with the number of hours devoted to scientific research. One study found that distinguished researchers in the physical and social sciences worked 60-70 hours per week for virtually the entire year..and all exhibited a driving absorption in their work.....To convince the skeptical sloths, let us move to a higher plane of evidence. In lieu of specific cases, suppose we examine group statistics. Wayne Dennis studied contributors to disciplines as diverse as music, linguistics,...and chemistry. He found that the top 10% who were the most prolific in each field could be credited with about 50% of all contributions to the field. In contrast, those among the 50% who were at the least productive were responsible for only about 15% of all the work. There is even a law that expresses how much the elite monopolizes a creative endeavor. According to the Price law, if k is the number of persons active in a discipline, then the square of this number approximates the size of that subset who produced half of the contributions.
A senior colleague of mine has done an interesting study. He has taken the 7th standard marks of all the professors working in the university and tried to find a correlation. The correlation coefficient was less than 0.1, indicating that performance at the school is not necessarily a good indicator of whether the person will become a professor in an academic university.
The article seems to imply that professors liking their jobs and working hard has resulted in students turning away from academics. A youngster can not complain that he has to practice for ten hours in the sun to make it to the cricket team. Sachin Tendulkar still practices as hard as anyone else in the cricket team. A youngster should instead marvel at Sachin working so hard (even after achieving so much) rather than complain ! Further, after completing graduate school, one need not work in a research university. One can work in teaching oriented universities, in industrial labs and so on.
In some instances, the requirement of working hard may also dissuade non-serious science "enthusiasts" Recently, in IISc, we admitted two graduate students for the master's program who had great ideas on winning the Nobel prizes during their course program. When it was pointed out to them rewriting the second law of thermodynamics will require them to first understand thermodynamics thoroughly (taking a course, for example) and then working hard, they left the program. I do not think, however, this was bad.
However, all this is moot. Science is supposed to be entertaining and engaging. In IISc, for example, you can find faculty working for 30 hours or 100 hours a week and get paid the same. Many of us work for long hours because one finds pleasure in doing this work rather than anything else. If graduate students are turned off because professors enjoy their jobs so much that they work hard, so be it.