Just nitpicking, but if the usual price is 10€ and you want to offload the 30% tax to the consumers, pretty sure the maths should be 10/(0.7) ≈ 14.29€

Huh? It’s the businesses that will suffer from that 30% tax. It’s like suddenly seeing your Netflix subscription being more expensive and that triggers this “do I even need it anymore?” evaluation

Has been this way for a long time. You pay through Apple, you pay more. You pay on the website, you pay the regular fee.

If it costs 13€ to support a 10€ Patreon pledge, then how do you expect the company to cover for that? Paying the creator less? Still, that will spawn competition, which again hurts the business

The creators are the ones who choose how they handle this. Either charge their 10€ tier as ~ 14.29€ or receive 7€ instead of 10€ when it comes to Apple users.

The businesses ain't gonna suffer shit.