To more accurately reflect the scope of what Google had to offer, all three stores were combined under the 'Google Play' brand.
However, Google's stores weren't nearly as popular, despite having wider availability. Google was taking the same approach as Apple, which keeps the App Store, Apple Books, and iTunes as separate entities. Unlike Android apps and games, the Google Music and eBook stores aren't exclusive to Android phones and tablets. Google Music launched in 2011 in beta, and while fans loved the local uploading feature, its library of music to purchase wasn't big.
Despite the large library, it was mostly filled with public domain titles and scans. The Google eBookstore launched in 2010 with over three million eBooks. It combined the Android Market, the Google Music Store, and the Google eBookstore.
The creation of the Google Play Store in 2012 was the culmination of three separate online markets that Google was running at the time.