It probably is at least relatively. The problem is that you (or at least a lot of people) wouldn't like the answer. Make it a very curated marketplace. Yes, that would take some labor but you can also take into account ratings etc. (Though not sure how to deal with the legit crappy online banking app that people give low-ratings too.)
But cue the outrage over my app dropped below a 4.0 rating and Apple kicked me out of the App Store. Or Apple decided I wasn't popular enough. Or any of the other ways in which curation produces losers that will be at least somewhat arbitrary at the margins.