Our Founding Fathers ostensibly believed in democracy - but their writings all point to a distrust of winning via popular vote. The Constitution does not specifically give anyone the right to vote - in those days this prerogative was given to the states to do as they defined what constitutes property and voting rights. These electors were appointed in those days by the states governors, people who were essentially elites and/or who owed favors to those governors. Thus, having these elites appointed as electors insured that elites would remain in power.
Why hasn't it been changed in all this time?
Not sure why, myself. But it is being considered by some.
Thanks, Gopher, I'd say it's time it was changed.