As far as we can tell, historically your assumption is wrong. Hard times do not really breed hard people it's a myth that comes from the antiquity and was used by philosophers and elites to link the moral corruption of a people with its inevitable downfall.
For instance:
> Under the assumptions of our Fremen Mirage, we ought to expect farming societies to be frequently overtaken and subjugated by their non-farming neighbors
Isn’t it basically the Vikings crushing their neighboors to get fertile territories ? That’s also France’s whole history, getting overrun in waves of invasions, backing up what he calls the “mirage” that is supposed to get debunked.
PS: in economic terms the counterpoint to his theory would be the resource curse, so it’s not a foreign to us concept either
Pirates would be the closest thing that comes to my mind, but it's more an economic activity inside a society than a separate culture.
The same way I do chores, but I'm not a house maid (until perhaps I quit my job)
Examples: Vikings, Barbarians, Huns, ...
Take a cat that has lived an easy life indoors its whole life and put it outside.
How long do you think that cat will survive outdoors compared to a cat who has lived outside its whole life?
Many people who have had too easy of an upbringing may seem emotionally stable while inside the safety of their cushy comfort zone, but when they're put outside their comfort zone and hit with a real challenge or hardship, they often crumble, because they never learned how to deal with real difficulty