Nice post. You posed a good question and provided loads of info. Having ingested the info though, I still would not consider chess to be a sport.
It is all about grey matter and physicality counts for nothing, so for me that makes it not a sport. To be classed a sport, you need to physically move in my opinion or throw something or hit something.
I do enjoy playing chess and have showed my 4 year old and 7 year old sons how to play. There is a crisp €20 in the chess box for the first of them to beat me! They both love to play now.
I recently watched the Queen's Gambit which was the catalyst to get the boys into chess. That's a cracking show in case any of you have not seen it yet.