I was not aware of that event, but not at all surprised it draws huge crowds. The Quarter Horse is the biggest breed in the US with over 2 Million of them (the US Thoroughbred population is less than half of that and continues to shrink on a percentage basis). Even in KY, there's a lot of Quarter Horses, as of 2022 there were 38K QHs in KY vs 48.5K Thoroughbreds out of a total of 210K horses in the Commonwealth. I have always liked Appendix Quarter Horses (which is a cross between a Quarter Horse and a Thoroughbred) which gives them greater sturdiness, more sensibility, greater ability for turning vs a Thoroughbred, but more stamina and ability to hold speed for longer than a Quarter Horse. That makes them particularly well suited for arena polo which is a substantially smaller field than a traditional grass field which is the size of approximately 9 football fields. And speaking of arena polo, as soon as I get back from my trip to Keeneland next weekend, the FIP Arena Polo World Championship will be taking place both where I played in college and for some years thereafter and the club I play at now (although playing grass polo now) with teams from France, Italy, Pakistan, Guatemala and of course the US and Argentina.