> Of course they are edge cases. How many people do you think install third-party apps on Android? Pretty sure hardly anyone does that.

Yeah, which is why no one with any sense is going to be fighting againist this. Third-party installs on Android are largely scams. I don't think you've thought this through.

> Also, Windows works pretty well with software from third-party sources, or would you forbid them in Windows as well?

Windows is well known for being insecure compared to others. Apple have also worked to secure users against third-party apps.

> Sure, there are the occasional crypto scams which disable a hospital here and there, but this can arguably be prevented by not giving non-admins admin permissions.

Don't they use local privilege escalation attacks as part of the attack?