The problem with a play-till-you-win match, is if it isn’t a final, it could ruin the final. Just look at Wimbledon… after that marathon Mahut-Isner match, Isner could barely play the next match. Now I hope I’m proven wrong, but there is every likelihood that this recent marathon Anderson-Isner semifinal is just as likely to have ruined the final.
Surely they could set things up so that is a full day’s rest between the semifinal and final.
One day’s rest is insufficient recovery time after an 11-hour match. (that was the length of the Mahut-Isner match)