Google is no longer supporting the ADT plugin, and it is actively encouraging developers to migrate to Android Studio. The official announcement about the ADT Plugin being DEPRECATED was posted on 26 June 2015 at https://android-developers.googleblog.com/2015/06/an-update-on-eclipse-android-developer.html. It is also clearly stated at https://developer.android.com/studio/tools/sdk/eclipse-adt.html.
Is the Eclipse Foundation still supporting and encouraging Developers to use Eclipse ADT for Android development, or did even the Eclipse Foundation give up and abandon Eclipse ADT? I am wondering if Android Studio and Eclipse ADT are still competitors, or if Eclipse ADT was defeated and they just gave up. It is obvious that Google wants everyone to use Android Studio, but what is the position of the Eclipse Foundation about that?
There is no competition at-all. Android Studio is de-facto industry standard now.
Eclipse ADT was built and maintained by Google and not by eclipse foundation. Android Studio is far better IDE then Eclipse ADT ever was. Google has long abandoned ADT for good and so did the industry.