I called this in January that PS3 games would see low sales. I straight up called it. The fact is there's too many games and the kind of users who go out of their way to support 1st party titles and research them online are stretched thin with all those games as well as the HUGE number of quality multi-plats. Your going to see the same thing with Resistance and Uncharted and Ratchet and Clank. They will all sell lower than their predecessors.
It has more to do with the quality of the games, as opposed to too many games. I'm not saying the games aren't good. They're just not good enough to outdo their predecessors. Although I do believe inF2 is ahead of inF1 and KZ3 is only below KZ2 by ~50k. The only major game I see being lower than its predecessor LT is LBP2.
Nothing's holding these games back from outselling their predecessors by a huge margin. They all have the potential to do so. It's up to the developers to use that potential. If a game doesn't outdo its predecessor, then it's mainly to due with the quality of the game itself.
As for this holiday, It's not exactly as packed as you make it out to be. Uncharted 3's going to be big, of course. (semi-big if you compare it to something like Gears, COD, etc). Resistance isn't exactly a big franchise. And the new Ratchet & Clank looks like a low-budget cash cow TBH. That just leaves us with one big game, a mid-tier game, a low-budget game, and a few HD collections which should bring in some nice profit.