After Tyson's loss to Douglas in Tokyo? In similar fashion, Foreman was also upset in on another continent. But... Did Foreman retain his mythical status after Zaire, similar to Tyson? How big of an upset was the Young fight at the time?
No, the mystique came off George right away. He didn't fight professionally for a long time afterwards, around 15 or 16 months. (He fought a couple of exhibitions, including one infamous one where he fought five bums one right after another, but the opposition was so bad that everyone thought it just made George look like a clown). His first match after the Rumble was a life and death fight with Ron Lyle, where he was down a couple of times. (In particular he got knocked flat on his face at the end of the 4th round and looked like he'd been knocked clean out). He had a couple of more fights before Young, but the only notable one was a rematch with Frazier. Only problem was this was after the Thrilla, so whatever Frazier had left was gone after Manilla.