A 51% staker who attempted to reverse transactions on ETH2 would be automatically penalized by the destruction of their stake. The network would keep running an

A 51% staker who attempted to reverse transactions on ETH2 would be automatically penalized by the destruction of their stake. The network would keep running and the end result would be a large sudden deflation of ETH. On PoW this would be like an attacker's mining rig burning down. A 51% staker who just censored transactions could hold out longer. If the problem were severe, the community would have to decide whether they want to manually fork off the attacker. The equivalent for PoW would be changing the hash function. Gaining 51% can be more expensive to do on PoS than on PoW. If 10% of the tokens are staked, you need to accrue another 10% of the total market cap. On PoW, if the annual inflation rate is 2%, the hardware is good for two years, and half the mining cost is electricity, then the total value of mining equipment is only 2% of the market cap, and that's how much you'll have to spend to get 51%. (If miners are rentable, then much less for a brief attack.)