@CGI
For me there is a massive difference between a 6hour game and a 10hour game. Also, the experience of the game itself needs to be taken into account as well as how one plays the game. So, I do (in general) agree with the OP and here are some specific cases that illustrate why:
Metal Gear Solid on the PS1. My favourite game of all time until Metroid Prime came out. I could have rushed through it and clocked it in 8.5hours or so, but that wasn't an appealing thought. I took my time, had fun exploring the areas and the different gadgets and soaked in the atmosphere and story. First time it took near 13 hours, and I played it through again 4 times! That's pretty amazing since I've only completed a handful of games twice.
God of War. Well, we have to ignore GoW2 since it was a lot longer than the other two. They were (especially GoW3) truly mind blowing games with sooo much appeal. I've finished GoW3 twice and sat through it while someone else plays 3 times.
That said, some games have SUPER lame single player modes, and anything under 10 hours needs to be pretty spectacular to warrant a purchase from me.
All in all - agreed.
