No specific development or discovery has caused the rise: improvements in nutrition, public health, sanitation, and medical knowledge all have helped, but the operative impetus has been the “stream of continuing progress.”One view is that increases will continue at least until life expectancy at birth surpasses 100. Jay Olshansky, a professor of public health at the University of Illinois at Chicago disagrees, saying:
...the rise in life expectancy will “hit a wall soon, if it hasn’t already....Most of the 20th-century gains in longevity came from reduced infant mortality, and those were one time gains.” Infant mortality in the United States trails some other nations’, but has dropped so much—down to one in 170—that little room for improvement remains. “There’s tremendous statistical impact on life expectancy when the young are saved,” Olshansky says. “A reduction in infant mortality saves the entire span of a person’s life. Avoiding mortality in a young person—say, by vaccine—saves most of the person’s life. Changes in medicine or lifestyle that extend the lives of the old don’t add much to the numbers.” Olshansky calculates that if cancer were eliminated, American life expectancy would rise by only three years, because a host of other chronic fatal diseases are waiting to take its place. He thinks the 21st century will see the average life span extend “another 10 years or so,” with a bonus of more health span. Then the increase will slow noticeably, or stop.Easterbrook's discussion of the social, economic, and political aspects of our graying future is well worth reading. The number of Americans 65 or older could reach 108 million by 2050, like adding three more Floridas inhabited entirely by seniors.
The nonpartisan think tank Third Way has calculated that at the beginning of the Kennedy presidency, the federal government spent $2.50 on public investments—infrastructure, education, and research—for every $1 it spent on entitlements. By 2022, Third Way predicts, the government will spend $5 on entitlements for every $1 on public investments. Infrastructure, education, and research lead to economic growth; entitlement subsidies merely allow the nation to tread water.