Apple is moving in the opposite direction in macOS, so I wouldn't hold my breath on them choosing to do this whatsoever. Sideloading goes against their entire iOS app philosophy.
This would also mean that Facebook would start sideloading and attempt to circumvent any of the tracking/privacy enhancements they've built in to iOS.
This would also mean that Facebook would start sideloading and attempt to circumvent any of the tracking/privacy enhancements they've built in to iOS.