The way I see it PS3 released globally by March 23rd 2007, PS+ didn't begin until June 29th 2010, so there was over 3 years with no Playstation Plus.
The IGC started with WipeoutHD, after that it wasn't until Burnout Paradise (2nd of June 2011 in PAL regions) that a AAA game was added, so over 4 years after PS3 launched.
Farcry 2 was the 3rd AAA game (PAL region), which released on the IGC in early Feb 2012.
Here's the link to the IGC games added to the PAL PS+ library:
https://en.wikipedia.org/wiki/List_of_Instant_Game_Collection_games_%28PAL_region%29
America: https://en.wikipedia.org/wiki/List_of_Instant_Game_Collection_games_%28North_America%29
For reference (according to VGC) PS3 had sold just over 38M units and moved around 276M units of software when PS+ began, PS4 may get close to those numbers by early next year, so maybe that's when more AAA games will land.
It wasn't until mid 2012 (5 years after PS3 was available globally and 2 years after the launch of the service) that Playstation Plus started to get a steady flow of AAA games added to the IGC.
People have definitely been expecting way too much too soon.
