See the part in the title that says "In 2009 dollars"? That's where it says it's controlled for inflation.
There's no measure that I'm aware of that shows a decline in productivity, in the USA.
GDP per capita is a pretty standard measure, because the per-capita means that population growth doesn't skew it at all. It's been increasing pretty steadily since your supposed "golden age". Beyond that blip around 2010, due to the recession, when it's continued upwards from that point.
If you mean a loss of
manufacturing jobs, specifically, that's
not a negative. The USA (and the entire Western world, really) is shifting from a service-based economy into a knowledge-based economy, currently. A manufacturing-based economy is a stage they have all evolved
past, because it's just a stepping stone to more productive economic systems. You may as well complain that there aren't enough people working in the agricultural sector.