Reviewing news coverage of the Core Technology Fee, usually glossed over is that the CTF applies to every install of a marketplace. From Apple:

Developers of alternative app marketplaces will pay the Core Technology Fee for every first annual install of their app marketplace, including installs that occur before one million.

Because marketplaces will usually be free, this makes it nearly impossible for them to work without charging developers just as much as Apple does, or having enough cash that it can lose money. Everything in Apple’s rules is designed to prevent anyone from using this.

@manton I think that's a misreading. The same Apple link provides a sample calculation of this fee for the Forest Explorer app: The first month the app gets more than a million installs, the fee is charged only for the installs above a million i.e., 50K (€ 25,000 @ € 0.5 per install). Furthermore, it's annual pro-rated for that month hence € 2,083 coz the installs may fall below 1 million the next month.

@pratik Forest Explorer is not a marketplace. It’s just a normal app. I’m talking specifically about apps that are marketplaces, like third-party app stores.

@manton Ah! So the entity that runs a marketplace app pays CTF for all apps in it even if one app has more than a million installs? I’m confused. I’ll need to read it more carefully

@pratik The marketplace needs to have an app in order to offer apps to install. The marketplace app itself is installed from a website, not Apple's App Store. The marketplace app itself is under the same terms as other apps, except that it does not get the 1 million install exemption on the CTF; it has to pay from install 1.

@pratik I wonder what is going to happen to SetApp. It has been a market place inside the App Store Never quite understood how they did it.

// @manton

@manton I don’t see how those rules will stand. Soon to get slapped down and forced to change or fined by eu again. Note Apple is pissing of developers. That’s not good if you want software.

@manton it applies to any app that stays in the App Store too. So you get double-taxed

@stroughtonsmith @manton Steve is that really correct? I was assuming so after reading it but on reflection this seems very unlikely. Unless I am misunderstanding, It would require both of:
1. you to install the app from the App Store *and* then delete and install it from a 3rd party app store (or vice versa) in a given year
2. AND it would rely on Apple not deduping these at least based on device. It seems like that must be happening as they still control the install process.