This doesn't make any sense. Cost disease occurs because workers can get higher pay in other industries. If manufacturing really is high productivity (as you imply), keeping it onshore would only make cost disease worse not better. Moreover, the fact that cost disease is happening despite the fact we offshored manufacturing suggests that productivity is increasing in other sectors. My guess is in tech, high end manufacturing, and finance.
Globalization commingles the economies of different countries. You can no longer talk about the US's labor force and the Chinese labor force as different things. Also rentier capitalism raised labor costs via rents.
Bonus: Services are not fundamentally productive like manufacturing.
