Apple doesn’t get the source code of apps. They check what apis you use so they can prevent you from using non public apis and they run some cursory checks. But there is a lot of crap on the App Store.
I really wish we had app stores actually require vendors to submit source code and build instructions so that the app store would build it themselves and publish it. Something like F-Droid even if the source code is not publicly available.
It's difficult to get useful code review out of colleagues working for the same company. The idea that Apple et al should have a competent reviewer audit each submission is simply not a practical thing for any type of repo that accepts software developed by third parties.
Sometimes a small comment in HN makes one think in a whole new way.
I agree with you that useful code review is a tough nut to crack. Professional editors exist for writing, and science has the peer review process (also flawed).
Reading code, is a whole different ball of wax from writing it (and from optimizing it in some cases) - I can think of few people who are great at both. I have to wonder if we will ever get to the point where "review" sits in an outside role/function that isn't already overloaded (team lead, architect, management).
Does the fact that we don't have dedicated code reviewers speak to its immaturity or (in)effectiveness.