The class most likely to have supported Adam Smith’s ideas would have been the middle class. The upper classes would not have supported him because his ideas would have harmed their interests.
Today, the idea of free trade is something that the upper class embraces more than the middle class does. However, in the late 1700s, the upper classes supported free trade and other governmental policies that Smith disliked. The upper classes did this because it was in their financial interests. They were the ones, for example, who were most likely to get rich from the restricted trade that existed because of mercantilism. They were the ones who benefitted from not having to compete with imports. This would have caused them to oppose Smith’s ideas.
By contrast, the middle class would have supported Smith. They were not rich enough to be the owners of the companies that benefited from trade restrictions. Instead, they would have been the people who had to spend more money when buying goods because those goods were protected from competition. If Smith’s ideas were put into practice, the cost of living for the middle class would have dropped. For this reason, the middle class would have supported Smith’s ideas while the upper class would have opposed them.