That would be a necessary step due to the deep difference between a traditional computer operating system and a phone/tablet. On the PC the user loads the browser, searches for a software doing X and is presented with choices in theory not filtered by whoever runs the search engine; on Android/iOS the manufacturer owns the only default installed repository interface, and users are instructed to grab apps only from that, skipping search engines, therefore excluding an app from the store equals to making it impossible to find for most users.