If you take out COD FPS are not really that popular on PS3 when compared with the 360.
Without COD
PS3 360 360 without Halo
1 car game 1 msc 1 FPS
1 FPS game 1 RPG 1 race
2 Sport games 1 TPS 1 RPG
6 action games 2 Action 2 msc
5 FPS 2 action
3 TPS
Franchise can only be counted once eg, only 1 halo, 1 cod, 1 Uncharted.
PS3 360
1 Race 1 msc
1 Sport 1 RPG
1 Platformer 1 TPS
2 FPS 1 Race
5 Action 3 FPS
3 Action
As you can see 360 owners prefer shooters in general, TPS/FPS. PS3 owners heavily favour action games.
Cod is just stupidly popular. Outside cod and Halo, action games are the biggest genre.