When European Tour members who lose their card start playing on the PGA Tour as a back-up plan, then you can start to worry about American golf.
Most American golfers go to college for four years and do not start gaining experience in professional tournaments until they are 21/22 years old. Of those who are 21/22, the majority of them go to the Nation Wide tour for several years where world ranking points are very small. If they're lucky, they will make it to the big show by the time they are in their mid-late twenties.
For the lucky Americans who earn a PGA tour card straight from college via Q-school, they spend the first years learning how to win, i.e. Fowler Vs. McIlroy.
Now, compare European and other International golfers who do not go to college and turn professional at 17/18/19 years old. They usually start their careers on a developmental tour where they learn how to win at an earlier age. After that, they join the European Tour around 20/21/22 years old where they can start to accumulate decent amounts of World ranking points on a major tour, and if they crack the Top 50, they automatically get into all four Majors and WGC events (8 events with huge ranking points). This allows non-American golfers to accumulate OWGR points at an earlier age and a faster rate than Americans.