It's an anachronistic election system. The states were seen as the primary governing entities. They would hold elections for their federal representation which would determine the electors who would need to physically travel to DC and then the electors would vote for president in person. Presumably they would vote in line with the voters of their state but were able to go with their judgment if something happened between the vote and the electoral college meeting.

It was always biased in favor of the southern states. Slaves got counted as population but couldn't vote. Now states use prisons for the same effect. That biases the outcome of that particular state to have disproportionate influence.

All states but 1 now use the EC to throw their entire influence behind a single party instead of proportional based on voters. Take California which is the most egregious example. Democrats hold complete power of state function. The majority of actual people are not democrats but the majority of voters are so they legislate that all 40 million people in their state give that many proportional electoral votes towards president. They aren't going to fix it because they get to allocate tens of millions of voters who didn't vote for them into democratic party electoral college votes.