I think besides the whole Lousoix preventing the worst part, you have to remember that it is not directly the Eorzean people's fault the calamity happened, and so did not see the need to completely and utterly fall into a state of anarchy. IIRC, after the 3rd, 4th and 6th calamities, people distanced themselves from the philosophies of their old societies because they blamed those tenets for what happened.