representative over Pure Democracy

Why did America end up with a Representative Democracy instead of a Pure Democracy?

A Representative democracy is founded on the principles of popular sovereignty. Where as a Pure Democracy is a democracy in which the power to govern lies directly in the hands of the people rather than being exercised through their representatives. The Representatives of a person running for president organizes everything for what the say a election period. They have to go in the peoples interest but they still have to disagree with some people.
Representative government makes it possible for us to have a better balance between geographic areas and populations. The House is composed of representatives who are elected according to population. The Senate is composed of representatives who are elected according to geographic area. If both houses of Congress were elected according to population, the states with the most cities would be able to put their own self-interest ahead of the states that contribute most with mining, agriculture, and forestry. If a purely democratic national poll were taken on every issue, the foregoing problem would be greatly magnified.
The main strength of the system of representative democracy is that it makes provision, through the Constitution, law and political institutions, for limitations on the powers which are exercised by governmental authorities as well as by private associations and groups. It provides institutional checks and balances. A pure democracy is the worst form of dictatorship, so our forefathers chose representative government which makes us a republic - not a democracy. Our enemies and those who listen to them attempt to make us believe that we live in a democracy. These same people want us to believe that we will be better off without the electoral college - so that solutions to all issues are decided by popular vote. If we were to move in that direction, life here would become even more intolerable with more laws enacted more quickly and more restrictions placed upon us. Freedom today is curtailed excessively by laws and bureaucracies. With even more curtailing of our freedom, we would be moving closer and closer to the situation facing the Russians before their more recent revolution.