There will be a lot of finger-pointing but Harris ran a great campaign and there was nothing anyone could have done to change the outcome. Nothing. It was just too late to fix things.
Culmination
I think this election was determined some time ago. This election was the culmination of the long-term “conservative movement” strategic campaign begun in the 1970s. The country has been subjected to decades of unanswered, well-funded propaganda and it has had its way with people. One by one conservatives inserted the right people into the courts and those people chipped away at the guardrails. Piece by piece the billionaires gained control of America’s information ecosystem and far too many people now believe what they’re told to believe. (The podcast “The Master Plan” does a very good job of explaining how this happened, going back to the Powell Memo.)
Corporate Dems
They got rid of campaign finance limitations. That inevitably led to moneyed interests gaining control of and neutralizing the Democratic party as an opposing force. Those we called “corporate Democrats” blocked reform after reform. And when there were majorities for reform anyway they refused to eliminate the filibuster, preventing majority rule from restoring the Fairness Doctrine, voting rights, campaign finance, and many other popular reforms that would have prevented what happened.
Inevitable
So I don’t think it was even about Harris vs Trump at this point. It was inevitable. We had hope that we could overcome it, but this was set in stone some time ago.