A measure, a single number, doesn't have much meaning without comparing it to something else.
The OP, PBS in this documentary, and I believe you, choose to compare the American experience to what once was. Assuming that you are correct (and I don't assume that) there is less opportunity here than once was in the days of yore.
I choose to compare the measure of the American experience to the experience elsewhere in many countries.
Here, it is what it is. To give the number meaning we can choose to use glass half full or glass half empty comparisons. Like most things in life, it's a choice.
I also think it's worthwhile to "care" about the American experience as measured in many ways, not just what once was.