I wish apple would allow side loaded apps. I'm not saying eliminate side loaded apps all together. Merely, it seems like its a binary view. Either allow side loaded apps and make no attempt to design the installation process with security features, or deny un-approved applications entirely in the name of security.

I think Apple's desktop solution to unverified developers is a good way to split the difference. Deny by default but allow whitelisting. They go even further under the privacy tab and only allow certain applications permission to access accessibility features or full disk access, etc.

This actually seems broadly similar to the issue with "self-XSS" and the developer console in browsers (which is hidden behind a couple of menus). So far most of the mitigations involve the site printing messages into the console telling users to not paste in anything here unless they are a developer.

Maybe it's a good idea to hide the "Allow sideloaded apps" under the developer menu in Android or something, or generally to display a scarier message.

The end result of this is largely to discourage competition. The Google Play Store is not good at security, and the prohibition on sideloading is far less effective at preventing infection than it is at preventing app developers from avoiding Google's 30% app tax.