In the cartoon, now-prosperous immigrants object to further immigration to America. The meaning behind the prosperous immigrants' shadows is that there is an underlying secret to how the immigrants became prosperous or their lives are in danger because they are more prosperous than the locals.
One feature that helped the U.S. grow in industry was the inovation.
When any state or country operates with a "command economy", this means that the government, instead of the "free market" or consumers, is in charge of determining output and production quotas.
