Denouement
The apparent victor in the electoral college, which as we are again reminded is how America chooses its President, is the Republican nominee.
There are many reasons why he won and she lost. No one can enumerate all of them.
In my post "No Hetero Godless Childless Capitalists welcome" I identified one reason 4 years ago when looking at campaign websites. It is the type of reductionist coalition building, identity politics, that each party, but especially the Democrats do. In short, the Obama campaign (which I supported despite, not because of, this) appealed to select groups (demographic group X, profession Y, issue voter Z) rather than speaking to Americans as Americans. To be clear, the Romney campaign did this as well, but not as well.
Further the Obama campaign did not even try to systematically cover the map with demographic groups, professions, or issue voters. This made many feel excluded. While some in those groups may say, "good, my turn", that's not how the others in the excluded groups feel, and voting is nothing if its not about expressing feelings. Reagan was a popular President because he spoke to all Americans, even those he disagreed with. Obama, to a less-successful extent, tried to do this as well.
Trump of course used identity politics well, just chose a different coalition than his opponent and thus a different set of identities. And his coalition produced a majority of electoral votes. And those voters decided to go for one form of identity politics because it had been used to explicitly exclude them in the past, and was used again this year in the other party. It is possible that an appeal to all Americans would have worked again, as it had in the 1980s and earlier, but that was not tested.
We can talk about sexism and racism and nationalism and xenophobia and economic hardship, and those are all contributing factors. It is certainly possible (if not likely) a different messenger would have resulted in a different outcome. But she is as white as he is, she has as many balls as he does, and his voters were wealthier than hers and the economy is far better than it was when the last Republican governing with Republican policies left office.
Voting is about expressing preferences and identifying with coalitions. In a two party system, each party seeks the narrowest coalition possible that guarantees victory (so the party's governing policies will be as close as possible to the preferences of the party members). One party's coalition was smaller than expected. Someone (everyone) miscalculated.