Let's look at the big picture. Apple is getting assaulted on multiple fronts about their payment system and app store. They got a HUGE win with the recent decision that stated they weren't a monopoly. Now they have some precedent, in the US at least.
In Korea, they are facing an ultimatum, open up to other stores. They basically have two choices, capitulate (the details don't matter), or leave. If they stay, they have to allow other payment systems stores and will quickly have to do that in every country. They lose some money, but probably not a lot and open the platform to more bad players, scammers, and malicious software. If they leave, they lose money, but every other country will pause and wonder if Apple will leave when the screws are put to them.
The reality is that the vast majority of consumers don't care about this, they just want to be able to buy their stuff and for it to work. If suddenly, they can't purchase an iPhone at their local store because the government scared off Apple, they're going to be pissed at the government, not Apple. Will Apple lose out if they leave and the stock take a hit, hell yes. But, Apple may see leaving as the lesser of two evils as it keeps their lock on the platform intact, regardless of the short term loss in market share. And if Google follows suit, the Korean government will backpedal in an instant.