I'm not sure how you define "viable" but Amazon has their own app store for Android. I recall that some years ago I installed it because they gave away paid ap

I'm not sure how you define "viable" but Amazon has their own app store for Android. I recall that some years ago I installed it because they gave away paid apps every so often. Looks like its still a thing: https://www.amazon.com/gp/mas/get/amazonapp https://www.amazon.com/gp/mas/get/amazonapp