Just because something is not perfect that does not mean it's worthless. Most things security things operate this way where it's impossible to stop all malware or attacks.

When analyzing whether something is a net good for society, I look not only at the value it brings, but the cost that it brings. The mobile ecosystem normalizing the idea that the vendor that sold you your everyday computing device is the sole arbiter of what can run on that device is of enormous cost to society, but anytime anyone brings that up, there's an immediate retort bringing fear, uncertainty, and doubt about software obtained outside of those centralized silos.

As I've said countless times before, the answer is clear. Operating systems can install software from repositories. The vendor of the operating system can provide a default set of repositories. Third parties can also provide their own repositories. Device owners can choose what repositories to install software from.

Saying that there can only be one true repository is carrying water for trillion dollar companies to further extract money from their customers.