Think back to 1967. The job you have today may not even have existed. The Internet, and all the jobs that have come with it, were decades away. The Detroit automakers were dominant. Quality of life was different, too: The median household income was an inflation-adjusted $40,261, compared with $50,303 in 2008. There were also a hundred million fewer of us; 1967 was the year the U.S. population hit 200 million. We passed the 300 million mark in 2006, and by 2050, there will very likely be more than 400 million Americans. The lifestyle of the average American may change just as much from 2010 to 2050 as it did from 1967 to 2006. The economy will especially undergo change.