You make the point that everyone is reading Ayn Rand - I wouldn't call the Fountainhead optimistic, exactly, its central message is that most of the community are mindless sheep, and the heroic architect blows his own building up to spite the sheep. I see that the hardback bestseller is Dan Brown (conspiracy) and the paperback bestseller is Lovely Bones (have you read it? it is gruesome beyond belief). In the nonfiction there is the cynical Freakonomics.
This is the culture you call optimistic? To an arch-pessimist, I guess that would look optimistic.
As for individualistic, only in the sense that we saw in The Life of Brian: 'we are all individuals'.
'As I keep saying, if you're going to offer opinions on the USA, you should really spend some time here. Yes the official culture is unremittingly optimistic and individualistic. I don't know where you hear this pessimism.'