There are a lot of unsolved problems with Proof of Stake, despite what it's proponents typically advertise, and many of them are believed by experts to be insurmountable.
For example, one problem with proof of stake is that private keys only have value while you still hold onto them. Once you sell your coins, your private keys are no longer worth anything, which means you could potentially even sell these keys to an attacker with no risk to yourself.
The attacker of course does have value though, if someone can gather enough private keys together for a specific snapshot in time, they can create an alternate history.
Another big issue with proof of stake is that once you have a certain amount of stake, through diligence you are always guaranteed to preserve that amount of stake. And even further, if you are a validator who approves transactions, your permission is required when someone else wants to buy stake. An attacker who is able to gain enough stake to commit an attack for a short period of time can commit that attack forever.
With PoW, hashrate requires heavy ongoing electricity expenses. Getting to 51% does not mean that you will stay at 51%, and there's little you can do to stop someone else from buying more chips to push you back below 51%.
There are a lot of other fundamental issues with Proof of Stake, and a lot of good reason to believe that it will never be viable in the fully decentralized, fully trustless environment that bitcoin thrives in.
For example, one problem with proof of stake is that private keys only have value while you still hold onto them. Once you sell your coins, your private keys are no longer worth anything, which means you could potentially even sell these keys to an attacker with no risk to yourself.
The attacker of course does have value though, if someone can gather enough private keys together for a specific snapshot in time, they can create an alternate history.
Another big issue with proof of stake is that once you have a certain amount of stake, through diligence you are always guaranteed to preserve that amount of stake. And even further, if you are a validator who approves transactions, your permission is required when someone else wants to buy stake. An attacker who is able to gain enough stake to commit an attack for a short period of time can commit that attack forever.
With PoW, hashrate requires heavy ongoing electricity expenses. Getting to 51% does not mean that you will stay at 51%, and there's little you can do to stop someone else from buying more chips to push you back below 51%.
There are a lot of other fundamental issues with Proof of Stake, and a lot of good reason to believe that it will never be viable in the fully decentralized, fully trustless environment that bitcoin thrives in.