Aside from setting up payment, all of those issue are still present with Apple / Google payments. The difference is 3% (MC, Stripe, Visa) vs 30% (Apple, Google). That 27% can easily cover those issues and far, far more.

In fact, it's worse. Payment & fraud disputes are also bound to the marketplace. What are the chances that app devs will end up being the ones eating big losses just to continue to exist?