I grew up (and now live) in rural Appalachia. The "American dream" is defined much differently here. The American dream is owning a trailer and not having to live off of food stamps.
Let's ignore the absurdity of comparing a 1980 $100k/year salary to a 2014 $100k/year salary. In most areas of the United States, six figures is enough to qualify as well-off. Compared against the backdrop of abject poverty, six figures is certainly rich.
My wife's cousin was talking to her about a new job he landed. He was giddy with excitement, as he told her he was going to be "making bank." The salary was $22k/year.
My point is that "rich" is relative to your geography and your upbringing. In most areas of the U.S., a six-figure household income is enough to have a warm place to live and healthy food to eat, with enough left over to provide security during times of famine