I don’t understand the argument that, if Apple allowed sideloading and third-party app stores, then companies like Facebook would pull all their apps from Apple’s App Store and release them exclusively on their own app store. Facebook can already do this on Android and they haven’t. You can still get Facebook, Messenger, Instagram, and WhatsApp in the Google Play Store and I don’t see any indications that this will change.
But maybe they do pull their apps and encourage the installation of their own app store, would that really be so bad? Would it really be so bad if Facebook made it more difficult to install their apps? Sure, Facebook could allow for more surveillance capabilities, but there’s a lot Apple could do at the system level to prevent that.
But the benefits of allowing third-party app stores and sideloading would be tremendous. Wouldn’t it be great if developers could distribute their apps directly to their users if they wanted to? Wouldn’t it be great if they could sell apps with upgrade pricing on iOS without having to wait for Apple to build in a mechanism for that? Wouldn’t it be great if we had a store like F-Droid available to find free and open source software?