This article summarized the history and function of the electoral college quite well. Those who oppose this piece should read this article to understand it better--and not rely on mostly the 2000 and 2016 results to make their point.
It is my understanding that the states, at any time, can change how it elects its EC electors without any approval from Washington or the political parties. Maine and Nebraska have made these changes. The rest of the USA could go this way at any time, state-by-state.
Why won't the states do this? We will use California as an example. But keeping the old EC rules, the state government (D) more or less forces R voters to vote D in the selection of the president. So the state government has no incentive to change its EC rules from a winner-take-all to the proportion of what the people really want.
And then, of course, let's assume one party takes the high road and the other doesn't. The good party splits its EC votes proportionally; the bad party keeps the old way. The bad party easily wins the presedential election!
What a mess the USA is in. Time for people to start writing a new constitution (no elites this time).