This doesn't mean that Biden can count on blowing Trump out of the water in the money race, even if voters start abandoning Trump in droves as the COVID-19 pandemic skyrockets far, far past what was seen in initial U.S. peaks in New York City and elsewhere. The reason is simple: Trump's base may be steadily whittling itself down to the thirty percenters—conspiracy cranks and racists that will never leave him—but enough rich people remain willing to put up with mass death and economic collapse in exchange for tax cuts and regulation-tweaking to keep his campaign fat with cash even if Trump himself is (cough) not particularly liquid.
The Washington Post notes that Trump will be holding a fundraiser next week in Hillsboro Beach, Florida. "The event is set to charge $580,600 per couple and is likely to inject millions more dollars into Trump’s reelection coffers." You don't need many donors when they're each willing to shove a quarter million dollars into your hands just for the privilege of being a part of the new American fascism.
I don't know who exactly would still pay $580,600 "per couple" to hear Donald Trump spit about all those who have wronged him, but we can assume nobody will be wearing masks. Please, then, have fun with that.