It was only because of the Electoral College system that Trump was designated winner.
The contest for the President is a contest of winning states. It is the “United States.”
Imagine if a baseball team, upon losing the World Series, started to complain: “Wait, Wait! We should win. This is all wrong. Sure the other team won more games, but we had more overall hits when you add them together. Therefore, we are the better team.” Not only is it disengenous to change the rules at the end, which, amazingly favors the losing team (imagine that), but in the end, that’s not the contest the teams were in. Measuing the winning team by total number of hits is just a horrible measure for naming a series champ.
But here’s the real kicker : even if the rules were to change, who’s to say the losing team would really be the winner? Each team would change its game play behavior from the start of the season to maximize hit count, instead of game wins.
Same with elections. Even if you were to change the elections to a popular vote, you can’t assume the vote would come out the way you think it would. For example, take NY or CA... or any Democrat stronghold state: there are many people that stay home because they know the people in NYC outnumber them. If it were a popular vote, you would probably see those people come out, affecting the outcome in ways you can’t predict. These systems are complicated. Changing one variable doesn’t imply, in any way, that the rest of the system remains constant.
In fact, I bet Trump would have won in a popular vote too - as long as those were the rules from the start and everyone had the opportunity to adjust their behavior.