Meanwhile people sleep on the streets in Greece,
from children to pensioners.
I have friends in Macedonia. They have a GDP of $5k per capita. And I witness nobody sleeping on the streets, when I visit them.
Isn't Greece a relatively wealthy country, compared to several others in Europe?
1) The cost of living.
2) The distribution of wealth.
3) Social safety nets.
So, if Greece has a higher relative cost of living, if the distribution of wealth is relatively more unequal and if they have a relatively worse social welfare system then, yes, they'll face hardship.
A key news story for me from a few years back was how an elderly man lit himself on fire (or hung himself? committed suicide in public anyhow) in a central square in Athens as a direct result of the hardship brought about by austerity measures. And this, in an as you say demonstratively wealthy country. Sickening.
...on average, and Slovakia also has (as far as the most recent numbers I can find) a lower Gini coefficient, so should have smaller numbers far above and far below that average.