I think if he drops out quite a lot of pigeons will come home to roost for him on 21st January 2021 and thereafter. I doubt he will be protected against lawsuits mounted against him because of embezzlement, tax fraud, defaulting on debt and so on after that. I suspect that even a Republican president might choose not to protect him, and I am quite sure a Democrat one wouldn't see the need to.
The lawsuits will probably take in the more criminal members of his immediate family as well.
That is likely to be what he is afraid of at this point. If he had not had the hubris to run for President and thought that winning meant he could literally get away with murder, he would not face the nemesis that awaits him.