I don't think he'll drop out at all but I truly believe he regrets, or will regret, winning.
This man has spent the last, what, 40 years of his life doing whatever the fuck he wanted, however he wanted and whenever he wanted. His houses are nicer than the White House. His plane is nicer than air force one (and we've already seen his request to keep flying it instead...) etc. Now he actually has to work, hard, and NOT be allowed to act as he always has while making no profit. He has to continue running his businesses too, somehow.
This isn't a career politician achieving the ultimate goal, this is a dude who's narcissism led him to win a game. And now he's stuck living a life he doesn't want for at least 4 years. Hard work every single day. He can't just wake up and say "no, im tired let someone else handle it". It's hitting him. He's 70. He spent his whole life being rich and doing whatever. And this is a massively insecure person. You dont think he's having huge doubts and issues right now? Of course he is.
Again, I don't think he bails, but I also think it should be obvious to most that he likely isn't a super happy camper at the life changes he's now faced with this late in the game.
Personally I think he sticks to it more for the negative backlash he'd get from the deplorables if he cut and run than anything else. Unless he finds a viable excuse to blame it on some bullshit and fuck the country even more on his way out.