Yes. There’s partisans who vote Trump no matter what, but there’s also a pretty large number of “low information voters”. Rather than being necessarily dumb, many of these are people from all kinds of different walks of life who just don’t follow politics that closely and prefer to follow things like dating reality shows or sports instead. These people are not really aware of what happened on Jan 6 other than that there was some sort of riot at the Capitol. They know Trump was charged with a bunch of crimes, but don’t know if they were real crimes or just politics. And when these people see Trump lying confidently and Joe Biden being barely intelligible in response, they like Trump better.

It sucks, yes. But it’s reality. Democrats need someone who can answer Trump forcefully. Or they will lose.