This in theory would work.... but every scammer that calls up vulnerable people to trick them into stuff would be getting them to change this option. Even if there was a prompt saying "enabling this can lead to scams, malware etc" the scammer would be saying "ah you can just ignore the next pop up".I'm for the market deciding these things, not Congress. It would be like forcing property owners to rent space to merchants they may not want in their mall/shopping center. Imagine an adult toy popup store in a mall parking lot.Apple could easily do this by creating on iOS/iPadOS this same panel that exists on macOS, with the App Store set to on by default.
That said,
Edit: Upon reflection the first part of what I wrote isn't an appropriate analogy. I just loathe the threats that Congress will do something because the Congress right now sucks.
Right now, vulnerable people have a device which keeps them relatively safe. Removing that option is going to increase scams a lot.
All so someone can side load what.... the odd game boy emulator or Fortnite?