I will mildly diverge from Oil and Bo to suggest that "disgraceful" is what give Trump's base a hard-on, and gets them to march to the polls in percentages only a demagogic populist can achieve. Fighting lost causes like some demented Fight Robot, be it the restoration of coal energy or the cancelling of a lawful election, is one of the core personality traits that keep Trumpistas so loyal. The most naive populist voter doesn't think "he's fighting because of his own bloated ego." He thinks rather "He's fighting for ME!"
I do think there's hope, if the GOTV folk can really leverage the fate of the 2021 Senate and the possibility of a unified Biden government in their pitch to Dems and Independents to go back to the polling stations (or mailboxes, or dropboxes). And yes, some voters are repelled not only by the Sore Loser stuff, but by the attempt to undermine their vote for Biden.
Out of state cash is a factor, but as the general election demonstrated, not as much as it used to be.