Caveat: It isn’t available in the app store in the EU, and is instead only available via the developer’s marketplace, AltStore¹. As far as I can tell, this genuinely isn’t because of greed, but because of a little detail in Apple’s EU rules (possibly wrong):

[…] Developers can choose to remain on the App Store’s current business terms or adopt the new business terms for iOS apps in the EU.

Developers operating under the new business terms for EU apps will have the option to distribute their iOS apps in the EU via the App Store, Web Distribution, and/or alternative app marketplaces. […] Developers who achieve exceptional scale on iOS, with apps that have over one million first annual installs in the past 12 months in the EU, will pay a Core Technology Fee. ²

The problem being, if you’re under the old terms, there is no “Core Technology Fee.” However, in order to distribute on another marketplace, you must opt into the new terms, meaning you now have to pay the fee even on apps that are distributed on Apple’s app store. Thus, if you distribute on the iOS app store in the EU for free, and lets say it gets 2 million installs, you get 1 million installs free… and you now owe Apple half a million dollars.

1. https://news.ycombinator.com/item?id=40067556
2. https://developer.apple.com/support/core-technology-fee/