“[sideloading] would allow customers to download apps without needing to use the App Store, which would mean developers wouldn't need to pay Apple's 15 to 30 percent fees.” https://www.macrumors.com/2023/04/17/app-sideloading-support-coming-ios-17/

Not a chance. Apple will just use another method to collect their "commission”: https://developer.apple.com/support/storekit-external-entitlement/

Remember: Tim Cook views our customers as THEIR customers, our sales as THEIR sales, and the 30% as what they rightfully deserve for gracing us with a platform that we provide no other value to.