How Does a Proof-of-Stake System Make a 51% Attack More Difficult Compared to Proof-of-Work?

In Proof-of-Stake (PoS), network control is determined by the amount of cryptocurrency a participant 'stakes' as collateral, not by computational power. To launch a 51% attack, an attacker would need to acquire 51% of the total staked currency, which is often a massive and prohibitively expensive capital investment.

Even if successful, the attacker's own staked funds would be at risk of being 'slashed' (destroyed by the protocol) as a penalty for malicious behavior. This creates a strong economic disincentive, as a successful attack would devalue the very asset the attacker holds a majority stake in, making the attack self-defeating.