The author concludes that social inertia plays a greater role in human behavior than the desire for comfort or safety. Historical evidence is offered in support: many technological innovations have been resisted by people who worked in "miserable" conditions without these innovations.

The author is making a phenomenon-hypothesis argument, observing a phenonenon (workers resisting innovations) and drawing a hypothesis about its cause (social inertia). This is then extrapolated to a general principle that social intertia is a stronger driving force than is a desire for comfort or safety.

To undermine this argument, we can undermine an assumption the author makes (including by presenting an alternative cause). We can also find evidence that runs counter to the author's hypothesis, which in this case could be evidence of situations where a desire for comfort or safety outweighed social inertia.

From observing situations where people resisted technological innovation, the author reaches a conclusion about social inertia driving human behavior. This indicates an assumption that social inertia was the reason for that resistance, or else the evidence would be totally unrelated to the conclusion. One way to weaken the argument would be to present an alternative cause, showing that social intertia wasn't the true reason.

The author also assumes that “many examples” of this phenomenon are enough to support a general claim about the relative power of forces determining human behavior. We could weaken by attacking this assumption, by finding contrary evidence that undermines the author's generalization.