I don't have much time to devote to super long games. As much as I love Mass Effect 1, 2 and 3, they take me months to play because I only play for an hour a day and not even every day. If I was still a kid I could spend hours every day playing games, but I'm not and long games take too much time to finish. I still play long games but I must say that shorter campaigns like Halo 4 don't overstay their welcome and feel very satisfying. If they are good enough I'll replay them a few times or more. With long games I rarely go back because I can't justify the amount of time it takes to replay what I've already experienced. At least with Mass Effect I could replay them as the opposite sex and do things differently. But most of the time I prefer games to be completable without requiring me to neglect my life.
Besides, look at it this way:
A movie ticket costs $10 for about 90 minutes. At that rate per hour a 10 hour game would cost about $66.66. It's pretty much the same amount of money per entertainment hour. Anything over that is just gravey.