While that's probably true, Apple could bring to iOS what macOS has been doing for years: code-signed apps that aren't distributed through the App Store and aren't subject to any of the App Store's restrictions (and can't guarantee the ostensible security benefits), but can still be "disabled" by Apple if they prove to be bad actors. On macOS, there are actually three states for this: signed App Store apps, signed regular apps, and entirely unsigned apps. Users get to tell the system what to allow and disallow. There's no really good technical reason for Apple not to allow at least the first two categories on iOS by now.

(That system on macOS is, for those who don't remember, called Gatekeeper!)