I am convinced it won't go anywhere. It is not prohibiting app installs outside the Play Store: it's enforcing that apps installed on certified Android devices are signed by a valid Play developer account.
If I understand it correctly, it means that you could get a valid developer account and never put your app on the Play Store. Instead people could sideload it.
If I understand it correctly, it means that you could get a valid developer account and never put your app on the Play Store. Instead people could sideload it.