like someone else already said, something like puppeteer should be a psn game. they could sell it for a lower price and still make the same money per sold unit or maybe little bit less but it would have potential as download only game.
i think it could be a success if it would be a 15 or even 20 dollar game (and 10 after half an year or so) and since the whole 15 dollar would go in sony's pocket it wouldn't be too bad.
i'm just not sure how games which release now for psn or xbox live will sell in the long run with the next gen arriving. something like castle crasher sold over years pretty well but that could be different with games releasing now for ps3 or 360.