>It is only by exploiting the surplus of large amounts of workers

Well, it's possible for a person to become a billonaire without directly doing this. I think it was said somewhere that Lebron James was one of the first wage billionaires, due to his 20+ years on top of the NBA.

But loosening the statement a little, if the person themselves hasn't its almost certain that the people that have paid them have (in the case of sports athletes, the companies paying for the ads).

Be that as it may, being a wage-slave billionaire still leaves you less exposed to direct first-hand moral dillemas than the CEOs of companies.