Dang, I could write a whole essay about this.
The bottom line is that the 21st century USA is vastly different from the USA of the Founding Fathers, in a multitude of ways.
Let me hammer on just one major point.
Back then, the president had almost nothing to do with the daily lives of the majority of people. The states were far more sovereign and pretty much ran all their own internal affairs individually. The president was tasked with representing the state governments to foreign powers. In day to day affairs, the federal government had little influence, or need of it.
All that's changed giganticly since then. States are really just provinces now, and the federal government dominates on most things. Think about the three biggest issues in the 2016 election, taxes and health care and immigration. None of those even existed back then. The president had nothing to say about them.
The president didn't represent the people, he represented the state governments. So, the state governments picked the people who the legislatures felt would best represent their interests, and sent them off to the Electoral College. Those representatives hashed out the best choice and made a decision. But there was no popular election involved, nor was there a reason for one.
Actually, there's already a huge effort to democratize America. According to the Constitution, state legislatures can choose Electoral College delegates however they choose. When states representing 270 EC votes decide to require their delegates to vote for the popular vote winner, the USA will be a democracy.
Check this out. It's a little closer than you might realize.
National Popular Vote
Tom