"It means my family can buy better stuff than they could 40 years ago for a much cheaper price..."
This can mean one of two things. You may mean you are from one of the wealthier families who have benefited from the decline of US hourly wages. If so, you're in a minority.
If you mean it in a more general sense, I don't think you understand the concept of the terms inflation-adjusted wages or real wages. The man in 2012 making less in inflation-adjusted hourly wages than his father did 40 years ago can not buy more with his wages. The amount of food, clothes etc. he can buy after eight hours work is less, not more. I don't think you understand what I mean by real wages or inflation-adjusted wages. The average American working 40 hours a week can not afford as much food, clothes etc. as he could 40 years ago. Because real hourly wages have fallen over the past 40 years.