单项选择题

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Some business books are like a CD recorded by a one-hit-wonder pop star. On the CD, the star’s original hit is padded with dross hurriedly bundled together to cash in on the star’s ephemeral fame. Consumers, at the end of the day, regret not having bought just the original hit song.
Work force Crisis grew out of an article by the same authors that appeared in the Harvard Business Review in March 200,1. Called It’s Time to Retire Retirement, it achieved fame of a sort when it won the McKinsey Prize, an award granted annually to the "most significant" article to have appeared in the publication during the previous year. It gained even more fame by association, being joint winner that year with what turned out to be Peter Drucker’s last article What Makes an Effective Executive for the publication.
Now here is the CD extension of that original hit. It takes the basic thesis of the article that the long-standing corporate practice of investing heavily in youth and pushing out older workers must change, "or companies will find themselves running off a demographic cliff as baby boomers age" and puffs it out to the 200-plus pages that hook publishers demand as a minimum.
The authors’ original article was already on shaky ground in stating that, as baby-boomers retire (people born between 1946 and 1964, the oldest of whom are just now reaching 60), "there won’t be nearly enough young people entering the workforce to compensate for the exodus". An article in the August 2003 issue of Organizational Dynamics, by Peter Cappelli of the Wharton School at the University of Pennsylvania, had already knocked that idea on the head. Mr. Cappelli took issue with the popular rumour that the retirement of baby boomers will bring about a shortage of labour. At least in America, there are all sorts of ways in which the labour market will compensate. Many baby-boomers, for instance, will work longer; and although the next generation is some 16% smaller than the baby boom generation the generation after that is bigger than both of them. Then there is migration and offshoring to smooth the imbalance even further.
Curiously, both sides cited the US Bureau of Labor Statistics in support of their case: Mr. Cappelli quoting its estimate that the US labour force will rise from 153m in 2000 to 159m in 2010; Mr. Dychtwald and his colleagues saying that the bureau "projects a shortfall of 10m workers in the United States in 2010". First there are statistics; and then there is what you want them to say.
The debate has moved on from being about labour shortages to being about the waste of resources involved in allowing workers to retire at what is, given current life expectancy and standards of health, the relatively young age of 60 65. To give Work force Crisis its due, it dwells only briefly at the beginning on statistical pyrotechnics to prove that "a large and prolonged worker shortage could severely reduce our standard of living". It then eases into a discussion about ways in which companies can redesign work in order to bang on to the workers they want to hang on to, regardless of age, in an era when people hop from employer to employer like never before. But it is more like elevator muzak than the hit first recorded in the Harvard Business Review.
We can learn from the fifth paragraph that ______.