The Constitution is full of checks and balances, and the Electoral College was created to put some balance in presidential elections. The will of the people matters, but it is filtered through states. In other words, the system requires some geographic balance.
In an editorial, The Mercury of Manhattan, Kansas, points out how much this matters for smaller states in “flyover country.”
The United States “remains a collection of states with different values and cultures and laws,” says The Mercury. “The Electoral College essentially creates a series of state elections, rather than one national election, and thereby tends to give more weight to the interests of smaller, more rural states, than otherwise.”
This makes sense. Political organizing is inherently easier in areas with higher population density—so big cities already have an edge, more even than their population alone would suggest. And big cities tend to have concentrated wealth, which gives them even more power. The American Founders were conscious of the fact that urban populations throughout history often came to view everyone else as serfs. The Constitution, including the Electoral College, is written to help protect people in states like Kansas.