The average North American is significantly wealthier today than they were in 1970. Compare an average car from 1970 and an average car today. Today's econo-boxes are Space Shuttles compared the caveman-cars of 1970 (Ford Pinto?). Both cost approx the same in inflation-adjusted work-hours.
Think about the TV that your average family was watching in 1970, and the average TV today. 60" 3D flat panel TVs for <$1000 in 2013 compared to ~$2200 (inflation adjusted) in 1970 for a 16" Motorola color TV.