How much is the developer fee? Does a developer who offers a free app have to pay anything beyond that fee?
$99 per year. No.
Your comment helps support my point. Apple offers an inexpensive access to their App Store. Free or inexpensive or expensive apps can get wide distribution and support for only $99 per year (per developer, not app). If someone needs to make money they can run ads or figure out a way to otherwise make money. A developer could also charge for an app and pay the developer fee + whatever Apple's commissions work out to be (15 - 30%).
Now, if a developer could make a free app but offer a subscription or other IAP with billing going through an external system, Apple doesn't get a cut of that. Maybe that's okay but Apple in that case is providing complete access to infrastructure for only $99 per year. What if that app pulls in $25,000,000 per year for the developer? That would be great but what if managing it, hosting it, etc. costs Apple $50,000 per year (I'm making up numbers of course for this hypothetical situation)? What if it costs Apple $150? What if it costs Apple $50 or $5,000,000?
Apple loses money if the costs of hosting, managing, etc. an app are higher than the developer fee. Maybe that works with their overall business plan but maybe Apple doesn't want to lose money on the App Store.
What's the solution? Increase the developer fee? Increase developer fees only for more popular developers? Increase the cost of other services or products to cover lost revenue in the App Store? Do nothing and take a hit in revenue? What does that do to the investments of shareholders?
Nothing I wrote was in support of Apple's current practices. My comments have been to point out that South Korea's law will most likely result in changes to how the App Store functions. Maybe it will be a net positive for developers. Maybe it won't be. I don't know enough and I don't think anyone knows enough to make that prediction.