The manufacturing sector plays a huge role in, the given country's, economic stamina/wellbeing/growth. In saying so, any changes to its productivity will have an impact on a long-term basis on economic growth. In this case, the "slowdown" of labour productivity, may result in lesser demand and supply (Decrease in AD and AS). Becuase AS decreases, prices are driven higher, thus, AD decreases as consumers/households are less willing or able to afford for a high quantity. With a "slowdown" in productivity, firms may consider laying off their human resources, in an attempt to stay healthy. With less company income, there are fewer government taxes from both firms and consumers. The increase in Unemployment means an increase in government benefits. So yeah it's not good for the economy on a long-term basis.
I hope I answered your question. It's a bit jumbled here and there. But if you have further questions, regarding my response, then say so. You are very welcome to :)
