Fuck Google
Hm. I know there was a dramatic push by Google to kill apps that didn't specifically target the latest OS. Two of the very best weather radar and storm tracking apps were victims. There was also a couple useful star chart apps that were killed too. Another one was a GPS app that showed satellite position and signal strength in a very useful manner, as well as providing a way to pull the latest AGPS correction factor.
The latest Google App Store requirements are very draconian, and designed to push people to the latest phones by turning older phones with older OSes into abandonware.
I think this would explain the drop in apps better than the GDPR.