They knew the practices and values which each maker incorporated into their work and products. Comments on those differences can be saved until another essay. Productive labor results in commodities or increased value of commodities. There is a moral quality to it. Non-productive labor renders services.
Revenue is exclusively the product of productive labor.
The only mode of increasing the annual produce of the land and labor is to increase either the number of productive laborers or the productive powers of those laborers. We are slowly coming to realize that service is bought by productive labor, too. Unless somewhere a surplus is created through production, there is no revenue to pay for services. Nature labours along with man. Therefore to degrade either Nature or man compromises the whole system.