MacOS has all of this, but none of this can protect against abuse of privileges or tricking customers into thinking their copy of an app is legitimate and entering third party information into it.
This process, agree with it or not, is meant to stop things that cannot be stopped with just basic security technology.
Ah, I see what you're getting at. Well, there's better ways of achieving that, other than just banning non-compliant apps. Like, similar to HTTPS, we could add "ticks" into the app toolbar (or something similar) to indicate "verified" apps. Currently, there's nothing preventing websites from impersonating other websites, except consumer vigilance and green ticks in the adderss bar.
This process, agree with it or not, is meant to stop things that cannot be stopped with just basic security technology.