You make a good point. In the age pyramid plots the group in the US born in the 1950's and 1960's appear to stop dying. For India it is the group born in the 1980's and 1990's. I agree that this has nothing to do with decreases in infant mortality.
Between 2005 and 2006 the age adjusted death rate dropped 3% in the US. The largest ever. Of this deaths due to either influenza or pneumonia saw the biggest decline, a 13% drop. The average life expectancy in the US is now increasing at 4 months per year. Between 1950 and 2005 the average life expectancy in the US was increasing by 2 to 3 month's per year. http://firstwatch.jwatch.org/cgi/content/full/2008/612/2http://graphs.gapminder.org/world/#$majorMode=chart$is;shi=t...
Rather, look at how the pyramids stop being pyramids through time:
http://www.nationmaster.com/country/us/Age_distribution
http://www.nationmaster.com/country/in/Age_distribution