I think the problem lies somewhere else then in marketing, Sony's exclusives this generation are great, but they arent big renowned franchises like the multiplats that have sold well.
RE5, GTA IV etc. etc. , they are big games but they appeal mainly to the most hardcore of the users, Killzone, Resistance , Infamous , Uncharted and Little Big Planet mean less to average console user than those big games that have been around for ages, and they failed to make them big like Gears , Assasins Creed or Wii series. In contrast MGS is a big franchise and it sold extremely well for an exclusive
And with limited userbase even big advertising push cant help it, Last Gen Sony had the biggest exclusives now there offerings are unable to adress the majority
