that's in-fact, exactly what I was trying to say, I would prefer to buy all chapters all at once, but truth be told, I personally would be a lot more inclined to buy GT on a whim if chapter 3 already exist even as "half a game" as opposite to buying GT by itself, like you said, it may take 4 years to get to the next chapter or 10 years for the full series;
I would be slightly disappointed if I found a secret hinting towards a third game if I played right now, but would be rather giddy to see the same secret with the knowledge the chapter 3 can be bought
hell, if you look at my own comments you'll see I was pretty bored on my first playthrough and didn't even bothered to get to the second area, but between the second and third post I did down there I was alot more engaged with the story and gameplay, it just so happened I found about GT somewhere in that time frame,
don't get me wrong, I'm eager to play GT as soon as I just have some money for splurging, but I wasn't even compelled to finished CS before stumbling across GT