The answer is simple!
In the US if you want to be a professional golfer you start out as a kid with parents who encourage you, sign u up for lessions, drive you around, get you to golf courses, enter you in junior golf teaching programs, take you to tournaments, bring you to a place to practice, and spend a TON of money and time doing all of this.
Only a few can afford all of this!
Plus in the US most if not all play in U programs so if the player doesnt get a schlorship tuition is another cost. Great womens golf programs at the U level are limited as well!
In S. Korea, China, Australia, Spain and other countries kids are entered into national programs at a young age at no cost. The kids are evaluated and the more talented players move on and up thru the national program.
The kids in these program do nothing but play the sport sponsored by the national program. Other countries Austria, Italy, France, Swiss, and others have a similar program for skiing and others for tennis.
In the US to excell at golf, skiing or tennis requires wealthy , dedicated parents to keep the kids moving along in the sport!
Plus in the US kids are kids, they're not in national programs at young ages and have lots of distraction!