The poor have something that the rich envy. They have little to lose.
We are more averse to losses than to gains. On average, a rich person dreads losing their fortune more than they are eager to double it. The richer you are, you have to lose.
If you merely have a few hundred Euros as savings, it can sit in your bank account without a second thought. If you had a hundred thousand Euros, you have to worry about its safe custody, the need to invest it wisely, tax considerations, hedging against inflation, currency risk, diversification etc.
Richness brings fragility with it. A rich person stands to lose a fortune in times of crisis or uncertainity. On the other hand, a penniless person can only get richer.
This principle applies not just to finance. When you speak in a new language, learn a new skill or enter a new profession, you have little to lose, since you are starting from scratch. Things can only get better. Whereas an expert in any of those fields has a repuation to protect.
The flipside of ‘nothing to lose’ is ‘everything to gain’.