I think Trump won in 2016 for the same reason that Obama won in 2008. Their respective opposition was so weak and/or so damaged that the winner became the lesser of two evils.
Hillary’s campaign was doomed when it was leaked that she and Was-a-man/Sgt. Schultz had conspired to rig the primaries against Bernie Sanders. While she kept most of her die-hard “we need a woman. any woman” supporters, those Democrats that were more of the Bernie mold (i.e. the far, far, FAR leftists) just sat on their hands in November. While it meant very little in the deep blue or blood red states, those lost votes in Michigan, Wisconsin and Pennsylvania were most likely the difference between a Trump and a Clinton victory in those places.
And as for McCain? Well, we could write a “War and Peace” length book on his problems in 2008 and beyond. Just leave it at “he sucked as a candidate” and Palin, like her or not, provided just too much cannon fodder for the in-the-tank press that year. Like they needed any more.
Your first paragraph is right on.
Back in Nov-Dec 2014 after Conservatives swept Congress, people started to focus on President in 2016. Go back to both Left and Right, R and D web sites.
No more Clinton! No more Bush!
That was the #1 comment on all chat rooms, including FR.
Neither Clinton or Bush ever figured out how to overcome that. A good 3%+ of Clinton vote was people who would have voted for Rubio but were anti-Trump.
And a good 5%+ of the Trump vote was voters who saw Trump as EVIL...but as the lesser evil. They would have voted for a Mark Cuban-Bill Gates type of Democrat.
Warren? She is a light weight in politics. Imagine if she ran against Niki Haley, a real Indian. :)