You may be smart and wise and know how to avoid dodgy apps, but can you trust everyone you want to have a private chat online with to not unwittingly install a screen recorder? And differently from PCs, can you trust everyone you chat with in real life to not unwittingly install an app that turns on the microphone and/or camera?
Don’t get me wrong — I want there to be 3rd party app stores, even if only because of the sexual Puritanism that Apple displays. That don’t mean there aren’t valid reasons to be extremely skepticism about any attempts to do so.
I think it's reasonable for Apple to make it difficult for shady third-parties to get you to install their malware-ridden app store, but I don't agree that the only way to keep users safe is to disallow any third-party app installs entirely.
Apple just currently has little incentive to do the former, because a) it's more difficult, b) they have a financial benefit to keeping everyone in their own app store.
Given that, it's naive to think that Apple's main motivation here is to protect users. Sure, that's a part of it (maybe even a big part!), but they could protect their users in other ways, but those other ways would likely hurt their bottom line.
And I think that is why people cry anti-trust all the time when it comes to this: in a perfect world where no one was motivated by profit (and consumer lock-in), we can imagine that Apple would find a way to open up the platform a bit more.
Don’t get me wrong — I want there to be 3rd party app stores, even if only because of the sexual Puritanism that Apple displays. That don’t mean there aren’t valid reasons to be extremely skepticism about any attempts to do so.