It sounds like how taxes work (or at least, how it would work if billionaires could somehow be made to pay their share). You don't exclude the people who basically pay zero taxes from partaking in your country's infrastructure, do you?
From a system perspective, I like it.
Developers of free apps don't have to pay Apple anything (beyond the $100/year). This is the crucial part - it's all these free apps that add vibrancy and vitality to the iOS app ecosystem (not so much your standard issue apps like Facebook or Instagram, because they are available on all platforms, so it doesn't really help iOS stand out).
If you make under $1 million, you pay 15%, which is likely pretty competitive compared to what third payment payment options have to offer (which usually works out to at least 10-12%).
And for the bigger apps, I have little qualms about making the likes of Fortnite and Clash of Clans pay.
So when you think about it, the current system is actually set up to benefit the smaller developers at the expense of the larger ones (who have themselves stood to benefit from Apple's lucrative user base and the ease of making App Store purchases). The people here are actually fighting for the opposite - to benefit your way larger developers at the potential expense of your smaller ones.