Warning: potentially inflammatory content ahead.
AFAIK, Eddy Cue is the one responsible for all this. He’s known to be a shrewd negotiator (with Hollywood studios and such), but the App Store has been a disaster for developers in many ways (as well as users, in some ways) for a very long time. Tim Cook has trusted lieutenants who shouldn’t be, and gotten rid of those who could’ve done a little better (Scott Forstall, I believe, was one of those).