In the last three decades of the 19th century in the US, wages doubled despite union membership being at historically low levels. The rise in wages was driven by the same process seen globally in every country that has experienced rapidly growing per capita GDP. As companies produce more per worker and compete for a limited pool of labor, they bid higher for workers. This results in greater value, in terms of goods/services, offered to the average worker, which, in monetary terms, translates to higher inflation-adjusted wages.