Although I side with Apple when it comes to Epic, I think apps should be allowed to have Out-of-App Purchases, without being forced to also offer IAP. V-Bucks through the browser, subscriptions through the browser, etc.
At the same time, I do think Apple offering the platform for hosting the apps and updating it has value, so maybe apps that are being monetized outside the App Store would have to pay an annual fee that is waived if you offer In-App Purchase? I don't know.
I know I'm not a fan of the idea of multiple App Store on my phone, though... and Epic's demand to have their Store be available on the App Store, with same device access as the App Store and usage of the Update mechanisms in place in the App Store is bunkers; either you want to offer something within the App Store, or you want to offer an alternative (which like I said, I'm not fond of). I also know I don't want the App Store to become a collection of App shells for which you need to pay (wether in-app or out-of-app) to get any functionality out of. Forcing people into the IAP model is surely dissuading people from doing that, to a degree... it's a complicated issue