Here's another possibility (and I apologize for being pessimistic / paranoid):

Trump and Kushner are very preoccupied with manipulating numbers (they did this with Facebook and Cambridge if what I've read is accurate). Remember that in the early days of the pandemic, Jared is supposed to have counseled his father-in-law not to worry about the coronavirus because it would affect primarily blue states--i.e. kill off the opposition.

Trump or whoever is orchestrating this particular segment of the campaign may have decided that the die-hards won't mind voting in person (and without masks / social distancing), so if Trump can undermine the people more likely to vote cautiously via absentee ballots by making in-person voting onerous (fewer minority neighborhood polling stations, numerous electronic "problems" with the machines, etc.) or by disqualifying mailed-in ballots through various means, then they can tilt the pinball machine in their favor.

I know this sounds like just another tin hat conspiracy theory, but Trump / Kushner skillfully manipulated the discrepancy between the popular vote and the electoral college in 2016.

For 2020, Trump only needs to shave a few points off ballots from moderates / liberals / Blacks / Hispanics in order to finagle an electoral college victory.

And should Trump defeat Biden (without having to stage a coup d'etat), we'll all be just as surprised as we were when he defeated Clinton. And after that, we'll blame Biden for the loss. And then Don Jr. will be elected president in 2024, and once again we'll be surprised.