The article is too long for me :dunno: ... I watched Prof Niall Ferguson's Ascent of Money on telly, it's a really good documentary on the subject. Anyway, from what I saw in the article, one of the reasons of the failure of a static equation is the fact that the markets are not stable in long run. Prof Ferguson had a whole episode on this "herd mentality" of humans. Humans do not behave in a predictable way, little uncertainties that we are supposed to ignore or not make a big deal out of, can quickly turn into stampedes.
What I concluded from the documentary was that there has been lots of equations in the last 2 decades, but all of them ignored the fundamental aspect of finance, ie, they underestimate human behaviour. Reading this article makes me think that the industry didn't learn its lessons in the 90s and they made the same mistakes again....