Yes, making the application freely available might work for commercial developers if the application is for example tied to some online service with a revenue model of its own, or is an application you seek to sell professional services for.

My company deals with 100% free software, developed with the community out in the open, and we still manage to make profit from it. Why couldn't mobile application developers?

I see maemo.org and Extras as a place to explore these new business models. The Ovi style of publishing apps with a license fee is a thing of the past, just made fashionable because Apple does it