I agree with VPrime and we could add that you also should keep in mind how long a technology already exists on the market. A new technology of course cannot have the same amount of games like an old technology.
But if you look closely then you will realize that the growth rate of new games is very high at Unity.

This tells something about how fast new users get into the technology and how fast they can come to a result, not only a little template scene, but a working prototype or even a game.

Newcomers will get quite fast into scripting engines like GS or Unity. Hardcore coders will rather tend to program in C++ (C4, Torque, Irrlicht, Ogre).

And all this has nothing to do with Indies. If you watch the latest Indies especially in Germany creating adventure games then you see that they often use what works best for the project (Ogre, Wintermute). They do not fear a programming language like C++ as a barrier to give up their dreams or to accept lower quality.

But I understand that all this is another story for hobby users with very limited time. Then an easy to understand product with very intuitive editor like Unity is a good choice.