Are Korean Credit cards too expensive and too cheap?

Merchants in Korea are being screwed.  Credit cards are very expensive to process here, about twice the cost of Australia and Australia is a lot larger country with far fewer people.  These fees need to fall.

My credit cards are actually too cheap here.  I have 2 visa cards at w5,000 per year of which one of the has the fee waved if you spend more than w1,000,000  a year (less than $1000) and my Diners Club card is w30,000 per year.  All cards include rewards in either discounts or points.  How can these cards be so cheap?  A Diners Club card in Australia costs $135 plus $77 for rewards.  In the USA a Diners Club card costs $75 and in the UK it costs 50 pounds.  Perhaps an increase in fees could reduce the amount of plastic issued in Korea, however who would move first?