Different markets. Most people going to Asia would not decide to go to the USA instead, regardless of whether they're business or leisure travelers. Willingness to pay is different. In some markets, there might be more or less competition on various routes of approximately the same length for USA vs Asia, and the cost structures (landing fees, for instance) could be different, as would be the taxes and fees (country and airport specific) that are added to fares so that they contribute to the overall ticket price.