I agree, however, the reality is also there's no legitimate American Pro Tour and hasn't been for a number of years. There's far more foreign players playing in American Major Events than there are Americans playing in International Events.
The American players are at a tremendous disadvantage in terms of competitive opportunities, funding, support, and good will from their peers, fans, and industry. This is due to a plethora of reasons, consequences and misguided business ventures.
The situation today is certainly not "apples to apples" when rating American players to the international fields. I seriously doubt if any of the world's players could beat Shane in a race to 72 (amount of golf holes played in major tournaments) or even races to 6, 3 out of 5 sets like in major tennis tournaments.
Pool has a lot of luck in the shorter races, and easier equipment conditions. Shane is still one of the world's top 5 players, he just hasn't had the critical opportunities at the ideal times........yet.