In short, this chart shows that while real GDP is growing (0.2%/year), the change in that growth is slowing every year. Maybe there are other explanations for the steady slow decline, like how we are no longer a manufacturing economy, but all in all, I would say it’s predictable of an aging society.
From 1970, the US dropped from about 0.3% increase in annual real GDP growth, and is now growing at 0.2% growth. Overall the downward productivity trend seems to be slowing, which is probably a good sign, but combined with a decreasing working age population, it probably does not matter much in the end anyways. If you look closely, we are actually losing workers for the first time, probably in American history:
You can run the numbers on FRED yourself, from which this data came, or download my CSV.