abolishing all labor law would vastly increase the size of the economy

[citation needed], as the saying goes.

Why does your list not embrace whatever political policies induce the fastest economic growth?

I agree that the list should include something like "Pursuing rapid economic growth". But (1) it would probably be a mistake for the list to pick specific economic policies on the basis that they produce the fastest economic growth, since then the discussion would be in danger of being politicized by, say, an advocate of some particular economic/political policy that happens to differ from the one assumed in the list. (Of course that would never happen if the OP declined to pick favourites in this fashion.) And (2) fastest economic growth should not be the only criterion, unless that really is the only thing that influences robustness, which it may well not be. E.g., a policy might produce faster growth but also greater danger of violent and destructive revolution. Or it might produce faster growth but also introduce more single points of failure where one asteroid strike or serious outbreak of illness or terrorist act could bring everything down.

To take an example you already gave: laws restricting how unpleasant employers can make their employees' lives may reduce economic growth but also make it less likely that there's a violent uprising by workers fed up of their unpleasant lives.

one major civilization that feel due to its own laws [...] Why does your list not include that kind of threat to civilization?

As I understand it, RyanCarey is interested in threats to human civilization as a whole rather than to individual human civilizations. Human civilization as a whole doesn't have laws, regulations, taxation, etc. If one nation collapses under the weight of its own regulatory burden then others will presumably take note.

(How widely held, and how well supported, is the theory that the Roman empire failed because of overregulation and overtaxation? It's not a claim I've heard before, but I am about as far from being an expert in late Roman history as it is possible to be. In particular, how widely accepted is this theory outside circles in which everything is blamed on overregulation and overtaxation?)