[cyberdrunk]

> What is fragile? We have had specialized roles for the entire history of society and it hasn't caused anything to crumble.

I'm not a historian but I can imagine that a medieval specialist, such as for example blacksmith, could very much fix his own house (or maybe even build a new one), grow food, take care of animals, make wooden tools, make some simple herbal medicine etc. I'm guessing a lot of he was consuming was produced by himself and his family. Today, for engineers it's the total opposite - we only consume things produced by others, and essentially by strangers whom we've never met.

Regarding fragility specifically, if a major crisis comes (say a war), the desk jockeys, esp. ones didn't have the wisdom to accumulate resources, will fare much worse than someone who's say running a homestead. If they did accumulate resources (provided they don't become worthless by hiperinflation etc.), they will be able to buy the essentials and hope their stash lasts until the end of the crisis.