Most people didn't believe the fascism stuff. Democrats have used that in literally every election in my lifetime. They got played by being the little boy who calls wolf.
Then Harris told the working class that nothing would change and Trump promised lower grocery prices. It doesn't matter that he was lying his ass off. Most people are not politically engaged enough to know there was zero chance of him keeping that promise.
And unfortunately this isn't an election where only the politically educated get to vote. All of those points are bangers in your local university bar with political science students and professors. But all the common person sees is the guy who was president the last time they could afford stuff saying he'll bring that back.
So yeah, Harris needed to actually do some campaigning, not just fear monger.