Take an IPA (iOS Packaged Application). Remove the identifying markers, digital signature, change the bundle ID. Lo and behold, it’s indistinguishable compared to an app you developed yourself. Install and pirate away.
On Android, it’s pretty well documented the majority of APK installs are piracy. Possibly over 90%.
Apple will almost certainly, if necessary, allow 3rd party App Stores if the law requires - but direct IPA installation is a pirate’s dream, let alone the actual malware bundled with. Unless the law deliberately and specifically requires it, it’s not happening; and with the strong piracy connections, it’s very unlikely the law will ever specifically require that feature.
Software piracy is a fact of life. Attempting to protect against it, and eating whatever (possibly imagined losses) are costs of doing business. That's been that case as long as there have been personal computers.
> On Android, it’s pretty well documented the majority of APK installs are piracy.
How many of those would actually lead to a sale, though? This is the same argument the music and movie studios always trotted out, and it's just as invalid now. Many people just won't pay for things, and will otherwise do without.
All iPhones contain developer mode settings that can be activated with a little song and dance and compromise security. There is zero chance any of your relatives will accidentally turn off these settings if they are not actively looking to do so. Sideloading could easily be put under this mantle.
Potential counterargument:
"What if my nephew falls for some sideloading phish scam when trying to download hacks for COD mobile? Then he would be encouraged to follow any list of steps to compromise his security"
Response:
If someone is going that far out of the way to compromise themselves no amount of bubble wrap is going to fix it.