There's a number of ways you can look at this election and try to explain what happened. A few thoughts:
---The democrats really have been taking up more centrist positions on crime, immigration and the negative side of wokeness is actually in retreat. And yet that didn't help. Was it too little, too late? Or does the not-paying-attention public need more time to absorb the fact that democrats are less clueless on border security and are not trying to 'defund the police' anymore (not that they ever really were) Or maybe that stuff didn't really matter. Maybe it's just a sea of disinformation at this point and no way through with sensible policy until we regulate social media?
---Kamala Harris was the wrong choice. She was never popular, so shouldn't have been chosen just because she was the VP. Should have been an open contest at an earlier stage. Biden should have stepped out earlier. (And please don't ask me "if not Harris then who" simply because I'm sick of answering the same question and having that same debate over and over again. The contest would have been necessary to determine who the best candidate was and allow someone unexpected to come to the front.)
---Inflation was what did it. Inflation may be low now, but prices are still high. It makes no sense whatsoever to blame the Democrats for this, but most people are not smart enough or don't know enough to realize this. Perhaps the democrats should have done a better job of focusing on inflation as the no 1 election issue. Or maybe there was nothing they could do.
---We need to just accept that most people are incredibly selfish and have no independent sense of ethics/morality. Their ethics are mostly or only due to social norms. The fact that a candidate is a truly awful person and obviously incompetent is a second or third tier consideration for most people. Some people say that the normal rules don't apply to Trump, like he is the only one who can win with no ethical standards. And yet we've seen around the world obviously awful people like Javier Milei, Bolsonaro, Boris Johnson win elections as well, so I don't think that's it.