i think one of the reasons why uncharted is selling better per week a year after release compared to gears games (yes bundles sold a lot of uncharted end of last year but it is also selling better weekly without bundle) is that uncharted is much more a singleplayer game and gears a co-op game.

seriously, i bought all gears games day one and would do the same with future releases  but i am not sure if i would buy all of them day one without friends also doing it. gears is one of the best games for co-op and you won't buy it when your friends already stopped playing it.

for me, uncharted franchise is better in singleplayer but it's not as if you have to buy it day 1 because of your friends or something which means it won't sell as much at release but it will sell as much over the years because less people buy gears for singleplayer.