Average life expectancy statistics are often very misleading.
US life expectancy averages, and infant mortality rates, for example, seem worse than other developed countries in part because US medical practice is a lot stricter about defining infants as dead. Newborns ( premature, etc.) defined as 'dead' in other Western countries are defined as 'alive' in the US, and extraordinary efforts are made to keep them alive. As the conditions which in other countries are considered death are quite extreme, many of these efforts fail, thus increasing the number of deaths, and therefore increasing the infant mortality rate and reducing average life expectancy.
There are many, many other sources of variance in the distribution of life spans. Averages, we should remember, are just the sum of observations divided by the number of observations. Comparison of averages can be very misleading.