On the other hand, I think you can release shared source and closed source software that is still plenty useful and beneficial. For example, I am a very big fan of how Unreal Engine is licensed. Yes, it isn't "open source" and it isn't marketed as such. You can't take Unreal Engine components and go use them elsewhere even if you're not competing with Epic Games. Still, they provide some extremely powerful and useful software free of charge to basically all independent game developers. I think that's fantastic.
But that's all aside from what open source is. Unreal Engine isn't open source and it doesn't do anything for the open source ecosystem. Which is fine, because the entire world doesn't revolve around open source.