They lost because hiLIARy was a Lousy Candidate who is not likeable and had no message other than it was "her turn". In addition, they lost because Identity Politics is eating itself. That trend isn't going to help in 2020.
There are a lot of reasons she lost. She had lost much of her appeal to young people and all the republican lead attacks and investigations certainly took there toll but I believe she still could have won if the democrats and most of the country had not taken it for granted that she would win. The voter turnout in 2016 was down from 2012 particular in states Clinton won. Looking ahead to 2012, I don't seed that happening again regardless of who the candidates are.
I suggest you pay attention to things like Evergreen College and the GOP Baseball Practice shooting. The Left is only going to get More Extreme and More Unhinged. Unless the Left Elite and their Media/Entertainment Mouthpieces start vociferously and actively condemning such violence, the Left will become increasingly marginalized.
The GOP baseball practice shooting was the act of a lone gunman, with no backing by any political group. In fact, his actions have been widely condemned by both sides.
Evergreen is a small very progressive college in Olympia along the Puget Sound that has had political demonstration almost ever year for decades. This year is really no different except it has captured a lot of media attention which brought in outside elements. There were threats of violence but no real injuries.
James Hodgkinson, the GOP baseball practice shooter is not representative of most liberals just as Jeremy Christian, the white supremacist Trump supporter who killed two people shouting while anti-Muslim slogans is not representative of most conservatives.
There is a lot of really dangerous propaganda infecting the country. Both liberal and conservative media outlets are circulating material aimed at driving the two sides to violence. Some of these outlets may be creating the propaganda, others are just repeating it but the ultimate purpose is to tear the country apart from within. It wouldn't surprise me if those responsible for the election inference are behind much of this propaganda.
Think that if it give you comfort. In reality, the violent identity politics that you Progs have sewn for a couple of generations is reaping the whirlwind.
These are some of your brown shirted shock troops in action: