First, thanks for such a thoughtful and intelligent article. I haven't read all of all the Respones, so I might be repeating something already written.
I do come down on the side of those who think 'human nature' is constant. What changes are our cumulative knolwedged, including advances in technology, and our material circumstances.
People in general have always wanted to be distracted from the drudgery and the anxiety that life inevitably includes. People in general have always feared and resisted new ideas.
What is different, I think, is how late-stage modernity (including, as I see it, the development of the 'postmodern' perspective) has turned 'individualism' into a fetish of self-centeredness and self-promotion. Even for people who claim to be 'socialists', that is merely a political 'meme' they brandish to express personal feelings, and politics is the platform they have chosen in which to promote themeslves. (For the record, I do not 'self-identify' as a 'socialist'--or as a fan of 'capitalism'.)
Fetishistic individualism does reinforce the cultural tendencies identified in this article. For people who might have the capacity to challenge the intellectual staus quo of a society, though, the greatest tragedy is that those people tend more and more to see themselves and others only in terms of that overarching cultural paradigm. Everything that is said or written is viewed through that prism. What people convey is all but irrelevant; its demonstrated value in the realm of self-promotion is what really matters.