I think of the Olympics for the most popular sports. 600-800 million people play chess in the world. Chess is a very popular sport and is considered a sport by the International Olympic committee. I think chess is probably more mentally and physically enduring than some of the sports already in the Olympics.
I have nothing new to add, so I'll repeat what everyone else has said, in case you missed it. Chess is not a sport, so it's not in the Olympics.
What a committee thinks is only important for that committee. For example, your city council forms a committee to discover that people with red hair dont pay enough taxes. It's a pointless observation, just like some committee determining tic tac toe, Monopoly, or chess are sports. They aren't. Physical "enduring" has nothing to do with something being a sport. It's athletic prowess, ability, skill, that makes a recreation a sport. Chess has none. If something is physically demanding to be a sport, then putting shingles on a roof is a sport.
Ultimately the main reason chess isn't, and probably wont be in the Olympics is viewership. Nobody would watch it so there is no point in doing it. Why would the Olympics, which depends on viewership, do something that turns off viewership?
"Chess players do not compete based on athletic prowess, but it is essential for elite chess players to be in excellent physical shape. Games between elite players often last 7, 8, or even 9 hours."