Their business model depends on you not looking too closely here. Apple has a lot of legitimate advantages, but they oversell the safety of the App Store quite a bit, and they also have an infamous review process for apps that deliberately hides both the reasoning and any sort of estimation of false positive / false negative rate. Google should have these sort of stats as well, but obviously neither company would publish them. False negatives should be observable by the public.

I'm a fan of letting users add repos from vendors they trust, so there isn't one centralized gatekeeper.