If I remember it correctly, Gamestudio was in fact too popular for Conitec. They hadn't the time and resources to support it any further so they gave it back to oP Group. And oP Group got obviously a good amount of money for developing Zorro and creating trading algorithms for a number of clients. As a business owner you do what gets you the best profit.

But Gamestudio is still a really good engine. The most important things it needs are updates to 64 bit and DirectX 11/12. For mobile development better use another engine like Godot. In my opinion the engine isn't really important for quality games. It depends a lot more on the personal skills of the developers. Of course, a good engine can save you a lot of time.