-Biden was an establishment candidate who didn't excite the Democratic base, just like Hillary was. His main selling point was that he was not Trump, just like Hillary.
-Democrats drastically reduced in-person campaigning as a result of the pandemic, while Republicans largely maintained their usual levels of in-person campaigning (indeed, exit polls showed that Trump won voters who decided their vote in October or later).
Yup. You could also argue that Trump wasn't really blamed for the economy as it was a result of a worldwide pandemic. Sure, he handled the health crisis extremely poorly, but the economy would have tanked under any administration. That was also the case in other countries with competent leaders.
