There's no question that giving away Poser would improve revenue for people selling Poser content. More users, more purchases. There's just a question of whether Renderosity would see a big enough fraction of that to cover the development costs of Poser.

If you made a free version with add-ons, what would you cut? You could split off the parts for content creation, e.g. the fitting room, but I don't know that anyone would pay for it (it is, at least, not intuitive enough) and discouraging vendors from supporting Poser is probably counterproductive too. You could make Superfly paid only, but that would interfere with its adoption. Animation?