You don't "have" to do anything. If I don't want to sell my product on the App Store, or if I have to make you pay more for it, I risk losing you as a customer

You don't "have" to do anything. If I don't want to sell my product on the App Store, or if I have to make you pay more for it, I risk losing you as a customer. That's a trade-off every developer is aware of. Most apps that can publish on the App Store, will still publish on the App Store. On the PC, Epic sometimes has to shell out a lot of money to get an exclusive release, because a lot of people just use Steam. However, a lot of apps can't publish on the App Store, because of the strict anti-competitive rules.