What role do people in the rich world play in the pattern of global stratification around the world, as represented by the maquiladoras?
People in the rich world help to perpetuate global stratification, but can also help to reduce it.
We in the rich world consume many goods. We tend to want these goods to be produced as cheaply as possible. This often causes companies to open low-cost factories such as the maquiladoras that you refer to in your question. When we buy from these companies, we do encourage them to continue to engage in such tactics. By doing so, we increase our own material possessions while taking advantage of the cheap labor of others.
At the same time, however, we can reduce global stratification. There are those who work in the maquiladoras who are making more money that way than they otherwise could. Some of these people might use the money they make in this way to improve their lifestyles or even to invest in things like new businesses of their own. In this way, our buying habits might actually help to reduce global stratification.