Why did the Romans not stop their aggressive policy after establishing control over Italy?

The Romans had a nation in which there was unity, a common idea. The Romans had well-developed crafts and trade. The conquest of Italy made it possible to expand the territory. The conquests did not stop there, since fertile lands were needed for the further development of the country’s economy. Access to the sea, the conquest of countries on its coast made it possible to further develop trade, create a powerful state.