There have been countless reasons listed why chess is not a sport. And there have been a couple reasons listed why some people believe chess is a sport (almost always related to competition, personal belief, or biased recognition by a non-neutral party).
There haven't been any new reasons why chess could be a sport, but every once in a while a new reason comes up why it isn't. I was playing a game a few days ago and we were talking about pieces (we are going to make an outdoor board and need giant pieces). So the pieces need to be high quality, so they don't weather in the rain and snow and sun.
Which then led to the topic of what happens if they do wear out. Will they still work? In sports, it seems like the equipment often is very precise, and if it wears out, the performance in the sport is jeopardized. In golf if the ball has a big crack in it, in tennis if the strings are faulty, in soccer if the ball is deflated, etc. In sports sub optimal equipment leads to sub optimal performance.
But it seems to me in chess, and checkers and many other board games, condition of equipment has no bearing on performance.
Some people like to say that the IOC claims chess could be a sport. But what IOC sport does NOT rely on high quality equipment for optimal performance? If chess is the only one, maybe that's a pretty big hint that chess shouldn't be included
chess is a sport, but it is not a physical sport. it's more of a mental sport.