The problem is they break the API all the time, and this leaves Google Play strewn with broken apps. This may break 1% of apps, the next release breaks another 1%, after 10 releases, 10% of the apps not updated are broken.
Here's an example, I go to Google Play and search for "ringtone maker" ( https://play.google.com/store/search?q=ringtone%20maker ). The #3 result for me (which can vary by location) is https://play.google.com/store/apps/details?id=com.anbu.ringt... . So I download the app, click the microphone, say something, hit stop and - "java.io.IOException: Unknown file format".
This is their 3rd result for ringtone maker, has over 5 million downloads and yet their record feature is broken. It used to work but Google changed the API. You can look at the app source code ( https://github.com/malizadehq/ringdroid ) to see where this app broke if you want. This is just one example which comes to mind, I can think of many.
They claim they don't break the API going forward but they do all the time.