Books are allowed to have time-consuming, deep narratives aren't they? Movies are allowed to express deep thoughts right? And if you love reading, and you're reading something good, you don't even realize the time has gone by. Films are at least ninety minutes or more, but with a good film, you barely notice the time fly. Playing games is the same way. If I'm playing a game I love, hours will pass, and I won't even notice. If it just so happens to have an interesting or well-rounded story as well, then that's just a bonus.
And say for example you are reading that book, or watching that film, but then you realize you have something else that takes priority to do. You put a bookmark in the book. You stop the movie. You come back to it later. Games aren't so different. Isn't that why games have checkpoints and game-save opportunities? Maybe games like Dragon Age and God of War can take hours upon hours to complete, but I doubt game developers think there are people playing the game straight for those hours and hours, with no breaks. Or else, why would the save function be available throughout?
While I'm not against the idea of whatever a "hybrid" game would be (a challenging game, without a time constraint), I just don't think that that's what important. I don't think when an author pens a novel, they think "I wonder how long it will take my audience to read this?" They just pen the novel as best as they can and leave the readers to allocate their own time accordingly. And isn't the gaming industry trying to get up on the same playing field as novels and the such? Game developers should think the same way: focus on making their games good, rather than worry about how much time the player has to play them. That's for the player to decide.