Biologically it makes sense, as we´re not built to live much longer than 40-50 years anyway.
Actually, I've heard that while the average life expectancy throughout history is between 40-50 years, that this statistic is largely influenced by the ridiculous mortality rate of infants and children. So on average, even with all the advances in medicine, adults don't live that much longer than they used to. More like 10-15 years longer, as opposed to 20 or 30. Then again, who knows how legit the information I got was.