Someone else elsewhere made this point: the widget makers are not generally capable of increasing their own productivity because they don't have access to the capital required.

This method of organizing labor and value which disallows workers' to gain anything from increases in their own output keeps them from ever being able to participate in it, leading to alienation from their jobs and living in a perpetual cycle of poverty.

Thats why they invented the joint stock company. Individuals invest their surplus wages in a joint venture in order to gain access to capital that costs too much for any one of them to afford.

They also capture these gains because the increased productivity of the company results in more products of greater value on the market. In short, they benefit as consumers.