The question whether excellence is desirable is apparently a silly one: we all want to be good, and excellent is more than good, so why not? Unfortunately, an easy answer is not always the best one. Excellence in research and teaching is expensive, and in a system with limited resources there is a necessary trade off between the number of institutions devoted to research and teaching and the amount of human and monetary resources allotted to each of them. How many students should an "excellent" Biochemistry course have? Which fractions of their time should an "excellent" biochemist devote to research and teaching?
The number of institutions devoted to research and training, and the number of students they accept, is essentially determined by the necessities of the country, which usually can be precisely estimated. For example in developed countries the ratio of physicians to the general population is in the order of 3:1000 (World Bank data). Under the assumption that the average activity timespan of a physician is 35 years, the medical schools of any given country should be able to form 86 physicians per year per million population. Is 86 students per teacher, implying one biochemist per million population, the "excellent" ratio for a Biochemistry course in an "excellent" school of Medicine? Would 43 be a more excellent ratio, implying 2 biochemists per million population? Or perhaps a ratio of 172 would be excellent enough, allowing to reduce the requirement to one biochemist per two million population?
Next, we can question whether the workforce itself has an impact on the quality of results. Many important scientific discoveries benefited from some luck: penicillin, smallpox vaccination, and digitalis are among the first examples that come to mind. Luck is by definition a random occurrence and the only way to increase our luck is to have more people working in research. More people cannot be all excellent, excellence being by definition a rare quality: we need a large number of competent scientists working in the field. Moreover the excellent, outstanding scientists, who make greatest contributions to the advancement of science, thrive in and are selected within the much larger population of competent scientists. The more one looks at it, the more excellence appears as a rhetoric device rather than a reasonable goal. The origins of the western culture lay in ancient books, that shaped our views of the world: the Bible, the Homeric poems, and the like. All of them have their heroes and heroines, because these make a captivating story. Yet Troy was conquered by an army, after Achilles' death: let heroes populate novels, and let us work for a larger and more integrated community of scientists and teachers.