Some games are really good and should be short. Their just different. Short narrative games are usually not the best. Some notable exceptions such as Gone Home come to mind. But some games are really good due to their shortness. I'm not a big iOS game player, but JetPack Joyride is delightful and lasts a matter of minutes. Bigger console releases are Lollipop Chainsaw, which is one of my favorites this generation.
One of my all time favorite games is Comix Zone, it is approximately 45 minutes long. There is no backtracking, you can not extend the playtime much without just standing around. It's fantastic!
I think the crux of the argument relies on the fact that gaming, in general has changed. The release of the XBox and PS2 marked an intense movement to narrative based gameplay. This narrative existed before, but was rare outside of RPGs. But, just compare the cinematic nature between FPS games. Halo is a cinematic game. For comparison, look at the king of Console FPS before, GoldenEye. Hell, even compared to Marathon Halo is a movie. Marathon kept all of the story in text found on consoles.
This move to a cinematic narrative has created an impression that length equals quality.
Although I think this is just half of it. The Playstation craze created a RPG craze. I remember a time when playtime was advertised along side the game. Sad times.
But some games are meant to be replayed. If Mario 3D World is a 2-hour 1-play-through experience, then it is a bad deal for $60 to me. For some people, that's what the game is. But for some people, Mario 3D World is a 60+ hour game. Comix Zone for me, is a 100+ hour game... even though it takes 45 minutes to beat. Hell StarCraft's playtime for me may be measured in the months. But this time certainly does not include the single player campaign.
