I really don't have much to add to Rosit's fine analysis, except to note that culture is a proximate interest, albeit the most important proximate interest, and one that - as I have written about extensively - affects our ultimate (genetic) interests. But, any complete analysis of the decline of the West must put EGI first and foremost. That would, as a matter of necessity, bring forth, directly, the race issue, the inability to deal with fully and honestly being, as Rosit suggests, a flaw in Penman's hypothesis. Also, while epigenetic modifications are may in particular contexts be important, there are many, on both the Right and the Left, with an axe to grind against "genetic determinism" that overrate the importance of epigenetics with regards to the final phenotype.
A reasonable analogy would be that the body is the hardware (computer), the genes are the software, and epigenetics may in part determine whether a particular software program is turned on or off. That's important, no doubt, but without the underlying software, there's nothing to tun on or off, without the software, the hardware is merely a paperweight, and - and this is crucial - not all computers are running the same software. If one computer has a particularly powerful program and the other does not, all the "turning on or off" in the world won't make up the difference. Epigenetics has become an over-rated meme.
Penman's grim prognosis is more or less correct, and having the pathetic "movement" as the major vehicle for preventing the racial-cultural disaster that is unfolding is part of the problem.
We need to start rebuilding now, before the collapse, and Der Movement is hardly capable of doing so.