This is a perspective which is easier to pull off in the first world.
That is a first-world perspective: Claiming that only first-world-ers can be happy through adversity.
I think the claim is that it's easier to find first-world-ers which experience less adversity.
What kind of adversity?
Of course. Water sanitation is a big thing. Access to affordable food, the list goes on ...
I would say, on the whole, people here are happier than people in Australia / Canada / USA (where I have lived).
Obviously there are some severely sick or malnourished people where that is not true, but it's actually extremely uncommon. There is a lot of food and water here.
You should remember that stoicism was concieved amongst the elite of their time and place, who worried least.
Modern population density also makes comparisons of the contemporary 3rd world with ancient Greece rather far-fetched.
This can be said about decadence also!
If you read Seneca, Epictetus and Marcus Aurelius, three of the main authors of the Stoa, that is probably the last conclusion you would come to. Seneca was accused of conspiracy and forced to suicide by Nero. Epictetus was a slave who was "so poor that he didn't have to lock up his house". Marcus Aurelius spent the last years of his life (when he wrote the "Meditations") on the battlefield. They were meant as self-reassurance in a very troubled time.
>Modern population density also makes comparisons of the contemporary 3rd world with ancient Greece rather far-fetched.
Rome, btw. Which was already relatively densely populated.