The problem isn't simply just the lack of game content, its also the fact the story isn't that good. At least for me, I played through the Xenosaga series and I actually like Episode 2 which is designed similar to XIII in the fact its just constant rails and corridors, little customization, and very minor sidequests that don't really open up until the end of the game or usually in small windows of opportunity. The game design is terrible but I still like the game cause I like the story, even if it was the weakest in the bunch.
Yes, this is what I meant

The more a game has to offer outside of the plot, the easier it is to enjoy a game with a plot you happen to dislike. It becomes a problem when you do not like the plot and there's not much else to experience. I enjoyed FFXIII's plot, and now it is one of my favorite games. If you do not like the plot of Hotel Dusk, you stop playing. I'm not saying that this in itself means that being purely story driven is a bad thing, what I am saying is that it is simply going to appeal to fewer people.