Though of course Apple's rules aren't always consistent, I have 2 separate apps currently on my phone that can/are running this (Google's Edge Gallery and Locally AI)
Can't be just a SaaSpocolypse. LLMs with the right harness could obliterate much of the TODO+ apps with a general assistant.
But it's more likely it's just walled garden + security theatre that'll keep them from allowing outside apps.
They've been slowly cutting them off of updates and/or taking them off the app store entirely.
See Anywhere and Replit. Anywhere was the #1 or #2 app and was taken off the app store entirely before being put on and then taken off again.
Last I checked, Replit hasn't received an update on the iOS app store in over two months due to reviews denying them.