It depends on the platform. For instance, Apple policies don't make this business attractive because it brings lots of limitations. But with Android I don't see

It depends on the platform. For instance, Apple policies don't make this business attractive because it brings lots of limitations. But with Android I don't see why you couldn't improve this space. I know some companies that are doing research in this field, trying to tie geolocation and ML with app reviews and recommendations. Another idea that comes to my mind (haven't seen this yet) is to set up some sort of monthly payment subscription that would get bundles of apps at a much lower price. If I was a mobile developer with an app with few downloads but potentially good, I would sell my app at a wholesale quantity for much a lower price in order to gain exposure.