I don't mean to call y'all out for bad memories, but... y'all got terrible memories, at least based on 5 minutes of research.
Strider -- released Feb, on PS+ in July. That's 4 months+. Also note there isn't a ton of ps4 games, so quicker turnaround is understandable.
Sports Friends -- May 6th, ps+ Sept 2. That's almost exactly 4 months.
Hohokum -- never been on plus at all.
Stealth Inc. released in July 2013. It was on ps+ April 8th, 2014. That's a huge time gap. Definitely far more than 2 months, not less.
From what I can tell, Jet Set Radio HD released for PS3 in Sept, 2012, not Nov.
It wasn't on PS+ till July 2013. That's a long time.
Jet Set Radio Vita was released Nov 20th, and put on ps+ on Nov 20th, so was a Day 1.
MORAL OF THE STORY -- sometimes it feels like you just bought the game, but really, you didn't. The smallest gap of any example so far was 4 months, which seems a fair amount of time to me, and that was during the ps4 launch window while there weren't many games that could be on ps+ in the first place.
Sources --
PS+ release date:
http://en.wikipedia.org/wiki/List_of_Instant_Game_Collection_games_(North_America)
Actual release date -- googling, usually then going to blog + wiki pages for verification.