I saw an interview where BIG George said that after that fight he secluded himself and wated to be left alone he didn't want to know anything he just wen't into his own world, I also remember him saying he would wake up in the middle of the night sweating during that time off.....
I mean BIG George was off for over a year after that fight.
If there would have been a re-match lets say 5-6 months later I think Ali would have finished him off sooner the 2nd time around as BIG George would still have flashbacks of their 1st meeting.