It isn’t that it exists. The Founders were very worried about the possible rise of a demagogue, and electors were supposed to vote their conscience. That no longer happens — and some states have even passed laws requiring them to cast their ballot in a winner-take-all allocation. The system we have could work, but it doesn’t. And turning it over to a popular vote might not be the best solution.
Let’s see. At the doorstep of the Electoral College we can lay Trump, W, and the end of Reconstruction in the South. How could a popular vote do worse?