What Is the Common Economic Incentive That Prevents a 51% Attack on a Cryptocurrency Network?

The common economic incentive that prevents a 51% attack on a Proof-of-Work (PoW) network is the immense financial cost required to acquire or rent the necessary hashing power. A successful 51% attack, which allows an attacker to control transaction ordering and perform double-spends, would likely cause the cryptocurrency's value to crash.

The attacker's specialized mining hardware and the spent electricity would then become largely worthless, making the attack financially irrational and self-defeating in the long run.