Mercantilism has been pretty well abandoned as an economic doctrine particularly since piling up unsaleable stuff has so many times proved to be a losing strategy!
If you increase productivity and make stuff cheaper, you will probably need fewer employees, yet the people still earning a living somewhere will have more disposable income because, lo and behold, they can buy stuff cheaper.
The unemployed remain unemployed under all these scenarios.
If you think there's still some fire in Mercantilism fire away ~
I'm not talking about any particular "ism."