How do we know that? Consider that if there's a pattern of 'financial industry becomes the most powerful | financial industry arranges society to serve its interests | society collapses | end of history, not even records remain of the catastrophe (hey, keeping records detracted from profit-taking)' then we'd observe similar results.

Not sure how seriously I'm arguing that, but it does seem that if the situation was sustainable/survivable there would be records of previous instances of that situation.