AFAICT someone realized that it was possible to make money with an animated dog app, and it got popular. Then dozens of others heard of it and made knockoffs, some just using the idea, some going farther and publishing apps with confusingly-similar names and icons. So now there are dozens of confusing, bottom-feeding apps swarming around this little pile of money when there used to be just one, and the Android app store is a worse place for everyone.
Searching an app store is about as effective as seeking medical/dating advice in your spam folder, so I don't bother.
Really? I'm sure at least some of these are made using (cr)AppyGEN: https://play.google.com/store/search?q=dog%20simulator&c=app...