I find the FUD against third party app stores on iOS to be simultaneously crediting Apple with providing immense amounts of security in its App Store, and believing that it would be incredibly helpless without sole control through its App Store. That's very contradictory, both in ignoring the many, many vulnerabilities and scams that have proliferated on the App Store through the years (not to mention other negative user experience), but also ignoring the great pains that Apple has in ensuring security through layers and mechanisms beyond the App Store.

iOS is more secure than Android not simply because the App Store is better curated than the Play Store, but protections built in its very own operating system model. There are permissions restrictions that Apple has guarded carefully and not subject to removal through the permitting of third party app stores.

Furthermore, because Apple still has ultimate control of its operating system, it can design a careful flow to enable the use of third party app stores and side loading. It can hide it deep in Settings behind multitudes of "are you sure?" windows and security checks. It can coax users not to relinquish protections.

Hell, if Apple embraced the whole decentralized app store idea, it can provide an AppStoreKit SDK and sets of standards for third party app stores to adopt, a sort of security certification system that they can choose to conform to and be recognized for meeting Apple standards, similar to Apple's verified third-party repair stores.

The idea that allowing third party app stores will doom iOS is an anti-Apple critique in disguise, because it claims that Apple is helpless outside of its App Store. There is a lot more Apple can do.