I could see a single Beatles reunion in 1985 for Live Aid. In fact, I could see them doing the same thing that Phil Collins (and I forget who else) did: namely, play the first set in London, get to Heathrow, take the Concorde to JFK and a limousine to the stadium in south Philadelphia to play the last set.
But after that, they go their separate ways, since they've pretty much done so anyhow: Paul McCartney is too far gone in the pop vein; Ringo is a glorified Vegas lounge act; George Harrison has pretty much dropped off the radar and his health isn't the best. John Lennon tried to maintain something in the way of contact with more cutting-edge material (as opposed to pop music), which is what one would expect he'd try to continue. Perhaps he might dabble in some sort of rock/classic fusion in the '90s (sort of Emerson, Lake, and Palmer without the bombast?) and on into the 21st century.
Divorce from Yoko? Possible, but page one for the tabloids--and a gravy train for too damn many lawyers.