Comment by fluidcruft

It seems like the ACTION_MAIN loophole could be fixed (eventually) if apps that declare it are required to actually be launchers. It seems like legitimate integrations should have more specific intents.

At that point, Android prompting if random game you just downloaded should be your defaut launcher seems pretty dangerous interaction for sneaky apps to risk. They either cause the user to bounce and report or the fools select it as default launcher, replace their launcher, can't provide the launcher functionality and break the user's home screen and end up getting reported in Play Store. I also assume actually getting published as a launcher-class app at that point brings automated testsuites and other requirements that will be burdensome for developers.