Re: "we lowered the commission rate for small developers to 15 per cent"
I never stated how much Spotify pays, because I don't know - Apple said it - and if it pays only the 15% it's because in-app sales generates less than a million only:
https://www.theregister.com/2020/11/18/apple_to_halve_commission_for_small_devs/
Still it's a roadblock to generate more revenues from in-app purchases because then Apple will apply its full 30% tax. It's more that the US government asks to businesses, and on revenues, not profits.
It still stand that Apple asks an higher tax to those that bring them more money - which is was I was saying - a win-win approach (for Apple only, of course).
But probably the party is over.