I should have said perform at a very high level of performance consistently.
Unlike other sports that have salaries.
Not to pick on you, but you don't know too much about professional golf. Players, in effect, have salaries in the form of sponsorships that pay them to wear certain logo'd clothing, and carry/play brand name equipment, etc.
Just like any other job, they must perform, or they lose their sponsor, or worse, their PGA card to qualify them for the tour events.