I think a lot has been said about pace and reaction time. The fact that the opponent on the other side of the net is more of a factor than the actual speed of the ball so your reaction time has to be really fast. But the technical details of reading spin, generating different angles of spin, and the contact you need to make to get heavy spin add a dimension to table tennis that I do not think exists in other sports. Yes, every sport has its challenges. And if a sport is easier, then the level of play for the top professionals has to be higher because of the competitive nature of sports in general. So in one sense things even out. But to give that little ball heavy spin on a loop stroke you have to catch the edge of the ball and dig into it at the same time. The amount of precision that takes is pretty wild. It does not matter if it is heavy underspin or heavy topspin. If you want heavy spin you have to make very precise contact with that little ball that is moving fast and the opponent's spin is determining the trajectory of the ball. With lower level players when you hit a loop that has heavy sidespin they will often swing and completely miss the ball. Adjusting to that stuff and getting that "brush" contact that makes it so that you can spin the ball back is pretty amazing, and that those things just start feeling natural as you practice is sort of outrageous. Also, when you loop underspin and find that contact where the rubber grabs the ball so you can dig in to the edge of the ball and then spin it. I don't think there is any other sport that has that much technical precision. When you compare a basement player who thinks he/she can play with a rated club player, the amount of technique and hard work that goes into just a small amount of improvement is a lot.