What you are equating here is apples and oranges. If you buy 3 full length games you are getting 3 full length gaming experiences. In buying 3, 3-episode blocks of the same game you are getting "more" content, but still a single gaming experience. This is not an equal comparison, especially since no one knows whether the added content will bring new features or it will just be akin to adding more maps with the same gameplay from previous episodes.
I don't see your logic here (entirely). When you buy 1 game, it has the same gameplay and relative content. So if 3 episodes contain the same content and relative gameplay as a full length title what's the difference. This argument would only hold true if they changed nothing at all in the course of 9 episodes. Which they have already stated is not going to happen. They plan to make adjustments, add new features and content with each episode. Of course this is all words. Until it happens we won't know.
It would not even be acceptable to compare the 9 Sin episodes to a trilogy of games such as Quake 1, 2, 3 since in a typical game trilogy the technology and features change with each installment providing a substantially different gaming experience with each new iteration. With episodic content I doubt that any extensive new features will be added with each episode because of the myriad of problems involved in changing core mechanics of a game.
You are making an assumption that the technology will not change. I think that's a major oversight. The Source engine is going under major revisions atm. And will over the next few years. Valve is moving towards episodic content, heck they've essentially been testing that model for 5 years now with HL1. Constantly adding bits here and there (for free). Using HDR as an example, this was a major rendering addition. More is coming, be sure of that. And unless Ritual does 0 changes to the renderer themselves, which I doubt, expect that they plan to do more with it. Also they are working on their own tech.
Geez I sound like a lame fan Boi.. (which I'm not.. believe me).
This comment was edited on Apr 6, 11:55.