The main way that Singapore has become so prosperous is through their extended entrepot trade. This became a trading post and this caused trade to increase in Asia with Singapore being one of the four main trading countries. The others are Hong Kong, South Korea and Taiwan. They are called the Four Asian Tigers. Their economy in their big cities helped made Singapore so prosperous.
Now, it has become even more prosperous due to their cities growing bigger. Tourism has become a big part of Singapore. Also, many businesses and companies are established here with their headquarters here. They are gaining money and strengthening their economy by providing more jobs to their citizens and producing many things to sell to other countries.