Can you help me understand how people believe that Biden can beat Trump?

Regarding the electability of Joe Biden in a general election, I don’t see how he has any chance vs. Trump. Obviously many people disagree with me, so help me understand the logic? What is different between Biden’s policies, and who he appeals to that will help him succeed where Clinton failed?

It seems that, like Clinton, Biden’s strongest support in many cases, is coming from states (such as SC) that are certain to go for Trump in the general anyways, unless I’m misreading things? Biden seems to be unable (or unwilling) to expand the party, or build enthusiasm.

I see so many areas where Biden is at a disadvantage from where Clinton was vs. Trump.

Compared to Clinton, Biden has a longer (and worse) policy record, including supporting segregation; he wrote the crime bill; he played a major role in pushing the Democrats into the Iraq war; he supported a litany of bad trade deals that devastated the rust belt; he has advocated freezing/cutting social security, medicare, and other entitlements, his disastrous bankruptcy bill, etc.

Furthermore Biden has the issue of his son Hunter, who has been a problem and will likely continue to be someone the Trump campaign will use against him. Even if there’s nothing illegal, there has certainly been some ethically bankrupt decisions.

Biden doesn’t have the advantage of being able to play the identity card (a woman, person of color, or even religious minority).

Biden also has the major problem that it appears he’s experiencing some kind of neurological degradation/impairment/whatever with many examples of him being confused about time, location, and slurring out non-sensical word salad, demonstrating recall memory failures.

I know there are smart people who think Biden is the way forward, so help me understand. Where will the energy for him come from? What groups of people are going to turn out for Biden in the general that didn’t show up for Clinton and why? In what ways is Biden’s campaign not a Clinton 2.0? What am I missing?