Final answer:
The cotton gin, invented by Eli Whitney in 1793, greatly increased the profitability of cotton and expanded the 'cotton kingdom' in the South, leading to an increased demand for slave labor and creating tensions over slavery's expansion into new territories.
Step-by-step explanation:
The technological development that forced inhabitants of the southern states to weigh the benefits of economic development and growth versus the costs of the expansion of slavery was the invention of the cotton gin by Eli Whitney in 1793. This invention significantly increased the profitability of cotton cultivation, leading to the establishment of the 'cotton kingdom' in the South. The demand for cotton fueled the need for more slave labor, which in turn sparked disputes over the expansion of slavery into new territories. The cotton gin, while a remarkable technological advancement, ultimately exacerbated the division between the North and the South over the issue of slavery, contributing to the lead-up to the Civil War.
Editor Henry Grady and other 'New South' proponents saw potential for economic diversification through the development of railroads and factories, but even these visions were tied to the fundamental infrastructure of slave labor. Furthermore, with the cotton economy booming alongside the market revolution, the domestic slave trade grew, leading to greater entrenchment of slavery within Southern society.