They didn't envision Senators being elected by the people either.
As a counter-point, the founders didn't envision the Electoral College except what the Constitution says ... it is left to each state.
Neither the Constitution nor Federal election laws compel electors to vote for their party’s candidate. That said, twenty-seven states have laws on the books that require electors to vote for their party’s candidate if that candidate gets a majority of the state’s popular vote. In 24 states, no such laws apply, but common practice is for electors to vote for their party’s nominee.
Most states have a “winner-take-all” system that awards all electors to the winning presidential candidate. However, Maine and Nebraska each have a variation of “proportional representation.” Read more about
the allocation of Electors among the states and try to predict the outcome of the Electoral College vote.