The virus failing to harm Trump and Christie hurt the fear narrative a lot. Ironically, the fear narrative will play a huge role in Biden losing. Democrat voters are convinced that they will immediately die if they step outside.
Their key constituents are people who cannot vote by mail: young people (don’t know how to mail a letter), blacks (not known for great displays of agency, much easier to pay preachers to run buses to the polls), hispanics (largely don’t speak English, don’t vote in great numbers anyway, postal service not a part of their cultural tradition).