Automation usually means an increase in productivity so now you can produce the same quantum of commodities with less manhours going into them. So their value is less then before, but because your competiton has not become more productive it sells pretty much for the same price as before and therefore you make an extra profit. That is the classic motiv for automation. Removing power from the workers is usually not the reason unless maybe in full employment. Unions have overall lost all over north America and Europe in the last decades. Within international competition nationally organized labour doesn't hold that much power.